(equation problem) with solutions For 10 questions, the standard is to get 10 points for one right question and 5 points for one wrong or not. Xiaohua finally got 55 points. How many questions did he get right?

(equation problem) with solutions For 10 questions, the standard is to get 10 points for one right question and 5 points for one wrong or not. Xiaohua finally got 55 points. How many questions did he get right?

Suppose he did a wrong question
10*（10-a）-5a=55
15a=45
a=3
10-3=7
A: he got seven questions right

Basic exercises of solving equations in Grade 6

1 2x-10.3x=15
2 0.52x-(1-0.52)x=80
3 x/2+3x/2=7
4 3x+7=32-2x
5 3x+5(138-x)=540
6 3x-7(x-1)=3-2(x+3)
7 18x+3x-3=18-2(2x-1)
8 3(20-y)=6y-4(y-11)
9 -(x/4-1)=5
10 3[4(5y-1)-8]=6
3x^2+27=0
3x^2-4x-4=0.
（2y+1)^2+3(2y+1)+2=0.
（x－2）^2－3＝0
2x^2－5x＋1＝0
x(8＋x)＝16
（2x－3）^2－2（2x－3）－3＝0
x^2－17x＋66＝0
（x+1）^2－2（x－1）^2=6x－5
4（x+2）^2=9(2x－1)^2

On the problems of congruent triangles
In the triangle ABC, point D is the midpoint of the BD side, De is perpendicular to the intersection angle of BC, the bisector of BAC is perpendicular to point E, EF is perpendicular to AB is perpendicular to point F, eg is perpendicular to AC, and the extension line of AC is perpendicular to point g. suppose BF = () and prove (auxiliary line cannot be added)
Point D is the midpoint of the BC side. Wrong number on it

BF=CG
It is proved that there are three conditions for △ BFE ≌ △ CGE
De is the perpendicular of BC → be = EC
Yizheng EF = EC
∠BFE=∠CGE=90°
So it is proved

What's 2:40 in English

two forty

The feeling of reading composition 400 words

Today, I finished reading the article "mosquito and lion" in Aesop's fables. It tells us that a small mosquito takes advantage of its own advantages and overcomes others' shortcomings, thus defeating the huge lion. But in the end, it is destroyed by spiders because of its arrogance. This fable tells us that we should not be proud of anything and that arrogant soldiers must

The 13 meter long steel pipe is cut into 14 sections on average, each section is full court (), each section is () meters long, each section is () of 1 meter long (), is () of 13 meters long ()

13/14,13/14,13/14,1/14

Solve the equation, 4x + 8x = 144, 6y-3y = 159, 13x-58 = 111

4x+8x=144
12x=144
x=144÷12
x=12
6y-3y=159
3y=159
y=159÷3
y=53
13x-58=111
13x=111+58
13x=169
x=169÷13
x=13

Calculation: 1 / 50 + 2 / 50 + +98÷50+99÷50=______ ．

1÷50+2÷50+… +98÷50+99÷50=150+250+350+… +9850+9950，=1+2+3+… +9950, = (1 + 99) × 99 △ 250, = 50 × 9950, = 99; so the answer is: 99

A problem in mathematics exercise book of grade two in junior high school
To make a cylindrical oil storage tank with the height equal to the diameter of the bottom, the design volume of the oil storage tank is 5m & sup3;. What is the bottom radius of the oil storage tank? (π goes to 3.14, and the result remains a significant number) it seems that I will, but
..

If the height is x, the bottom radius is 1 / 2x
（1/2x）²π×x=5
1/4x³π=5
Do it yourself

The original price of a commodity is 289 yuan. After two successive price cuts, the selling price is 256 yuan

289×（1-x）²=256