The area of a square flower bed increased by 69 square meters after the side length increased by 3 meters. How many square meters is it now?

The area of a square flower bed increased by 69 square meters after the side length increased by 3 meters. How many square meters is it now?

Let a square be x meters long
（x+3）²-x²=69
6x+9=69
x=10
So area = (10 + 3) × (10 + 3) = 169 square meters

The plural of battery

batteries.

A + B = 5, C = root 7, sinc = 2 / 1, find the triangle area
Sinc = 1 / 2 is 1 / 2. It's wrong

(a + b) & sup2; = 25 = A & sup2; + B & sup2; + 2Ab, so a & sup2; + B & sup2; = 25-2ab
∵ sinc = 1 / 2 ∵ COSC = 150 ° or 30 °
According to the cosine theorem
That is C & sup2; = A & sup2; + B & sup2; - 2abcosc
Then 7 = 25-2ab-2ab × radical 3 / 2 (rounding off because the result AB is negative)
Or 7 = 25-2ab + 2Ab × radical 3 / 2
The solution is ab = 18 / (2-radical 3)
S △ ABC = 1 / 2absin C = 9 / (4-2 radical 3)

Use the passive voice to make a sentence of the general present tense, the present continuous tense, the general past tense, the present perfect tense, the past continuous tense and the general future tense

I am / is / are + being + V. past participle + by sb. E.g. their classroom is being cleaned by

What is the direct theoretical source of Marxist philosophy
A ancient Greek and Roman Philosophy B German classical philosophy
C 17th century English philosophy D 18th century French Philosophy
Tell me if you know. Thank you

B the outstanding achievements of Hegel's philosophy and Feuerbach's philosophy in German classical philosophy are the direct theoretical source of Marxist philosophy. Hegel is the epitome of German classical philosophy. He is the first philosopher who comprehensively and consciously narrates the general movement form of dialectics. He systematically criticizes metaphysics

What is the property of RLC series circuit when series resonance occurs

The circuit is resistive because the inductive reactance is equal to the capacitive reactance, the phase is opposite, and the reactive power is 0

6. In the process of persisting in combining the basic principles of Marxism with China's specific reality, our party has achieved two historic leaps, which took place in the new era

In the course of more than 80 years since the birth of the Communist Party of China, it has led two great revolutions, realized two historic leaps of combining Marxism with China's reality, and produced two theoretical achievements

When to add es, when to add s, when to go, what to add

Plural forms of various nouns
The plural form of a noun is usually followed by s after the singular
Day, days
Dog, dogs
House, houses
S after P, K or F is read as / S /. In addition, s is read as / Z /. When s is added after CE, Ge, se or Ze, a syllable (/ iz /) should be added to the pronunciation of the word
Other plural forms
B words ending with the letters o, CH, SH, SS or X, with ES at the end to form the plural: tomato, tomato
Brush, brushes
Church, church
Kiss, kisses
Box, boxes, boxes
But the plural form of loanwords or abbreviations ending with the letter O is just s: dynamo, dynamos
Kilo, kilos
Kimono, kimonos
Photo, photos
Piano, pianos
Soprano, Sopranos soprano
When a word ending in ch, SH, SS or X is followed by es, the word is pronounced with a syllable (/ iz /)
When C ends with y, but the consonant before y forms the plural, first remove y and then add ies
Baby, babies
Country, countries
Fly, flies
Lady, ladies
When a noun ending in y but with a vowel before y forms a plural number, it directly adds s: boy, boys
Day, days
Donkeys donkeys
Guy, guy
D has 12 nouns ending in f or Fe. When forming the plural, remove f or Fe and add ves
Calf
Half
Knife
Leaf
Life
Loaf (loaf of bread)
Self
Sheaf bundle
Shelf
Thief thief
Wife
Wolf
For example:
loaf,loaves
wife,wives
wolf,wolves
When the nouns hoof, scarf and Wharf (wharf) form the plural form, the words can be added s or ves at the end of the word:
Hoofs or hooves
Scarfs or scarves
Wharfs or wharves
When other nouns ending in f or Fe form the plural form, they directly add s: cliff, cliffs
Handkerchief, handkerchiefs
Safe, safes
Some nouns are plural by changing their voiceless form
Foot, feet, feet
Goose, geese
Louse, lice
Man, men
Mouse, mice
Tooth, tooth
Woman, women
However, the plural of child is children, and the plural of ox is oxen. F. some animal names have no plural form
The noun fish usually does not have the plural form, although has the fish this form, but is not commonly used
Some species of fish usually do not have the plural:
Carps
Cod cod
Mackerel mackerel
Pike Pike
Plaice flounder
Salmon salmon
Squid
Trout
Turbot turbot
However, if these nouns express plural meaning, their verbs should use plural form. If other fish and shrimp want to express plural meaning, they should add s at the end of the word
Crabs crab
Eels
Herring
Lobsters
Sardines sardine
Sharks
Deer and sheep have no plural forms
One sheep
Two sheep
When people who like hunting say duck, partridge, pheasant, etc., they all use the same form regardless of the singular and plural
ducks partridges pheasants
When hunters use the word game to express their prey, it always takes the singular form, followed by the singular verb. G, there are some unchanged words:
Aircraft, aircraft
Craft ship
Counsel in the court
Quid a pound (slang)
Some units of measure and numerals do not have plural forms. (see Chapter 36.) for uncountable nouns, see section 13
H collective nouns such as crew, family, team, etc. can be used as singular or plural verbs; if we think that this word represents a group or unit, we can use singular verbs:
Our team is the best．
Our team is the best
If you think it means all the members of the team, use the plural verb:
Our team are wearing their new jerseys．
All the members of our team are wearing new sweaters
When these nouns need to be followed by possessive adjectives, the plural verb + their is more commonly used than the singular verb + its, although sometimes both can be used:
The jury is considering its verdict．
The jury is considering the verdict
The jury are considering their verdict．
The members of the jury are considering the verdict
Some words are always plural and are used with plural verbs
Clothes clothes
Police
A garment consisting of two parts is plural:
Breeches
Pants (men's) panties
Pyjamas pajamas
Trousers pants
A tool or instrument consisting of two parts
Binoculars binoculars
Glasses
Pliers forceps
Scales
Scissors
Shears
Spectacles / goggles
There are other words in the plural:
Arms weapons
Damages / compensation
Earning income
Goods / wares
Green vegetables
A courtyard, ground
Outskirts
Painstakingly, painstakingly
Particulars
Premises / residences
Riches wealth
Savings
Spirits spirits
Stairs, stairs
Surrounding environment
Valuables
Some words ending with ICs are plural in form and usually follow plural verbs
Acoustics
Athletics sports
Morality / Ethics
Hysterics hysteria
Mathematics
Physics
Politics
For example:
His mathematics are weak．
He is not good at mathematics
But the name of the discipline is sometimes singular:
Mathematics is an exact science．
Mathematics is a precise science
K is plural in form but singular in meaning
The news is good．
The news is very good
It also includes the names of some diseases:
Mumps epidemic mumps
Rickets, rickets
Herpes zoster shingles
This category also includes the names of certain games:
Billiards
Bowls (bowling)
Darts
Dominoes dominoes
Chess
Some loanwords from Greece or Latin change according to their original rules when they form plural
Crisis /'krais /, crises / kraisi: Z / crisis
A printing or writing error, Corrigendum
Memorandum, memoranda
Oasis /'eisis /, oases / + u'eisi: Z / Oasis
Phenomenon, phenomena phenomenon
Radius, radius
The end of a railway or bus
But some loanwords change according to the rules of English
Dogma, dogmas
Formula, forrmulas formula
Gymnasium, gymnasium
The two plural forms of some words have different meanings
Appendix, appendixes / appendices
Appendices (of a Book)
Index, indexes
Indices
Musicians usually use the plural form of Italian musical terms
Libretto, libretti opera script
Tempo, tempo
But it is also possible to add s directly at the end of a word
librettos tempos
Plural form of M compound noun
Usually, the last word is plural
Boy friends
Break ins
Travel agents
For example, man and woman are in the first part of a compound noun
Men drivers
Women drivers
2. When a compound noun composed of verb + ER + adverb forms a plural, it is only necessary to change the first word into plural
Eater, flatterer
Lookers on the lookers
Runner's up
In addition, when a compound noun composed of noun + preposition + noun becomes plural, the first word also needs to be plural
Ladies in waiting
Sister in law
Ward of court
3 acronyms can also be plural:
MPs (members of parliament)
VIPs (very important persons)
OAPs (old age pensioners)
UFOs (unidentified flying objects)

If the height of a cylinder is 10 cm and the height is reduced by 2 cm, the surface area will be reduced by 25.12 cm square. What is the surface area of the cylinder?

What is the circumference of the base of the cylinder
25.12 △ 2 = 12.56 (CM)
What is the base radius of the cylinder
12.56 ﹣ 3.14 ﹣ 2 = 2 (CM)
What is the base area of the cylinder
2 × 2 × 3.14 = 12.56 (cm2)
What is the side area of the cylinder
12.56 × 10 = 125.6 (cm2)
What is the surface area of a cylinder
12.56 × 2 + 125.6 = 150.72 (cm2)

a. B and C are different prime numbers. A = AAB, B = ABC, the greatest common factor of a and B is______ The least common multiple is______ ．

Because a, B, C are reciprocal