- 2x - {4x-2y - [3x - (2Y + 1)]}, where x = - 2 / 3, y = 2008

- 2x - {4x-2y - [3x - (2Y + 1)]}, where x = - 2 / 3, y = 2008

The original formula = - 2x - {4x-2y - [3x - (2Y + 1)]}
=-2x-[4x-2y-(3x-2y-1)]
=-2x-(4x-2y-3x+2y+1)
=-2x-4x+2y+3x-2y-1
=(-2x-4x+3x)+(2y-2y)-1
=-3x-1
When x = - 2 / 3, y = 2008
The original formula = - 3 × (- 2 / 3) - 1
=2-1
=1

How to merge similar items! (2x? + x) - [4x? - (3x? - x)] For detailed methods and ideas!

=2x^2+x-(4x^2-3x^x+x)
=2x^2+x-(x^2+x)
=2x^2+x-x^2-x
=x^2
Note: x ^ 2 is the square of X

5x+10=5y 4x+4y=8 X, y are required 2. Settlement: (2x-3y) ^ 2 - (y + 3x) (3x-y) use multiplication formula to calculate and decompose factors

From 5x + 10 = 5Y ① We get 5x-5y = - 10, that is, X-Y = - 2 ③ From 4x + 4Y = 8 ② X + y = 2 ④ (2x-3y) 2 - (y + 3x) (3x-y) = 2x-3y) - [(3x + y) (3x-y) = (2x-3y) ° - [(3x + y) (3x-y) = (2x-3y) Ω - [(3x + y) (3x

3x-7+4x=6x-2．

By shifting the term, 3x + 4x-6x = - 2 + 7,
By combining the similar items, x = 5

Mo did a math problem: there are two polynomials A and B, B = 4x? - 5x + 6, find a + B. This student mistook a + B as A-B, and the result is 7x? + 10x-12. Please find the correct answer of a + B for him

（A+B）－(A-B)
=2B
=2（4X²-5X+6）
=8x²－10x＋12
The original formula is 8 x 2 - 10 x + 12 less than the actual one
So the original formula = 7x? 2 + 10x-12 + 8x? 10x + 12
=15x²

Given that the system of equations 2x-3y + Z = 0, 3x-2y-6z = 0 and XYZ is not equal to 0, find X: Y: Z

2x-3y+z=0 ①
3x-2y-6z=0 ②
It is obtained from ① × 6
12x-18y+6z=0 ③
It is obtained from ② + ③
15x-20y=0
15x=20y
x=4y/3
By substituting x = 4Y / 3 into 1
8y/3-3y+z=0
-y/3+z=0
z=y/3
Therefore, X: Y: z = 4Y / 3: Y: Y / 3 = 4:3:1
Answer: 4:3:1

Factorization 4x ^ 3-8 ^ 2Y XY ^ 2 + 2Y ^ 3

4x^3-8x^2y-xy^2+2y^3
=4x^2(x-2y)-y^2(x-2y)
=(4x^2-y^2)(x-2y)
=(2x+y)(2x-y)(x-2y)

Factorization (x + 2Y) ^ 2-4x ^ 2

(x+2y)²-4x²
=(x+2y)²-（2x）²
={(x+2y)+2x}·{(x+2y)-2x}
=(3x+2y)(-x+2y)

Factorization (x + y) ^ 3 + 2xy-2x ^ 2y-2xy ^ 2-1

(x+y)^3+2xy-2x^2y-2xy^2-1
=(x+y)^3-1+2xy-2xy(x+y)+2xy-1
=(x+y-1)[(x+y)²+(x+y)+1]-2xy(x+y-1)
=(x+y-1)(x²+2xy+y²+x+y+1-2xy)
=(x+y-1)(x²+y²+x+y+1)

How to factorize the square of (2x + y) and the square of - (x + 2Y) It is calculated by the square difference formula

(2x+y)^2-(x+2y)^2
=(2x+y+x+2y)(2x+y-x-2y)
=(3x+3y)(x-y)
=3(x+y)(x-y)