How to find the value of XY in mathematics problem (the textbook of Beijing Normal University) Find the value of XY Given xy = - 2, X-Y = 3, find the value of (x + y) (X-Y) - Y & sup2; + (X-Y) & sup2; - (6x & sup2; y-2xy & sup2;) △ 2Y Please settle it by 9 o'clock tonight,

How to find the value of XY in mathematics problem (the textbook of Beijing Normal University) Find the value of XY Given xy = - 2, X-Y = 3, find the value of (x + y) (X-Y) - Y & sup2; + (X-Y) & sup2; - (6x & sup2; y-2xy & sup2;) △ 2Y Please settle it by 9 o'clock tonight,

(x+y)(x-y)-y²+(x-y)²-(6x²y-2xy²)÷2y
=x^2-y^2-y^2+x^2-2xy+y^2-3x^2+xy
=-x^2-y^2-xy
=-(x-y)^2-3xy
=-3^2-3*(-2)
=-3

1、 Fill in the blanks
1. The algebraic expression 4xy3 is a term and the degree is
2. The algebraic formula is a term and the degree is
3、(2x2y+3xy2)－(6x2y－3xy2)=________________
4、 =__________________
5、(3x+7y)·(3x－7y)=________________
6、(x+2)2－(x+1)(x－1)=______________
7. Fill in the appropriate algebraic formula in the brackets: 2 - [2 (x + 3Y) - 3 ()] = x + 2
1. Cut the four corners of a square cardboard with side length of 4A into a square with side length of a (as shown in the figure), so that it can be made into a cuboid without cover, and calculate the total area of the figure after cutting
3、 Calculation questions
1. Calculate 20012 2 with complete square formula and 2004 × 1996 with square difference formula
3、(3x+9)(6x+8) 4、(a-b+2)(a-b-2)
5、(3mn+1)(3mn-1)-8m2n2 6、(2x2)3－6x3(x3+2x2+x)
7. Fill in the appropriate number in the brackets;
53 × 63 = 30 () 5N × 6N = 30 (); if 105 = 10N, then n = ()
Solution equation: 3x + 1 · 2x + 1 = 62x-3
8. (1) simplification: (2-1) (2 + 1) (22 + 1) (24 + 1) (232+1)+1
(2) Please write down the number of the result

3. (2x2y + 3xy2) - (6x2y-3xy2) = 6xy2-4x2y5, (3x + 7Y) · (3x-7y) = 9x2-49y26, (x + 2) 2 - (x + 1) (x-1) = 4x + 57 2 - [2 (x + 3Y) - 3 (x + 2Y)] = x + 2

People's education press primary school sixth grade mathematics book 102 page 15, 16, 17 answers (formula) thank you,

15 questions: 3.14 * 1 * 15 = 47.1, 3.14 * 1 * 1.2 * 15 = 56.52
Question 16: surface area: 3.14 * 10 * 2 / 2 * 20 + 20 * 20 * 5 = 2628
Volume: 3.14 * 10 * 10 / 2 * 20 + 20 * 20 * 20 = 11140
Question 17: surface area 5 * 5 * 34 = 850
Volume: 1250
10 cubes

If the third power of X is the sixth power of - 8a, x =?

The third power of X is the sixth power of - 8A
The third power of x = (- 2A ^ 2) ^ 3
x=-2a^2

Page 11 and page 12 of mathematics exercise book 1 of Grade 7 Volume 1
I forgot my exercise book,

Is it Pep? I have this one in eighth grade

Arrange the positive and even numbers into 5 lines according to the following table
Column 1 column 2 column 3 column 4 column 5
Line 1 2 4 6 8
Line 2 16 14 12 10
Line 3 18 20 22 24
Line 4 28 26
Then 2010 should be in line () and column ()
A. Line 126, column 1 B. line 126, column 2
C. Line 251, column 1 D. line 251, column 2

The answer is d
Analysis: Line: August 2010
Lie: look at the law

Write all the multiples of 15 within 100, where the odd number has______ Even numbers have______ ．

The multiple of 15 within 100 is: 15, 30, 45, 60, 75, 90. The odd number is 15, 45, 75. The even number is 60, 90

A kind of children's story book was delivered to the bookstore. It sold 30% on the first day, and 120% on the second day, 30 more than the first day. How many of these story books were delivered to the bookstore?

30% × 120% - 30%, = 30% × 6%, = 500 copies; a: there are 500 copies of this kind of story books from the bookstore

There are 10 red, yellow and blue balls of the same size in the box. There must be three balls of the same color in order to feel them, at least a few balls

Seven
Two red, two yellow, two blue
Add any one, and you'll get three of the same color

How to solve (x-1) ^ 2-1 greater than or equal to 0

(x-1)^2 >= 1
Then, there is (1) X-1 > = 1, that is, x > = 2
② x-1