Second grade math problem: the numerator of the following fractions and the polynomials in the denominator are arranged according to the power reduction of X (or y), and then do not change the value of the fraction, and make the numerator The coefficients of the highest order term in the denominator and denominator are positive (1) - X / 1-2x-x squared (2) - (3y-7y squared) / 5-7y + y squared To process

Second grade math problem: the numerator of the following fractions and the polynomials in the denominator are arranged according to the power reduction of X (or y), and then do not change the value of the fraction, and make the numerator The coefficients of the highest order term in the denominator and denominator are positive (1) - X / 1-2x-x squared (2) - (3y-7y squared) / 5-7y + y squared To process

（1）
-The square of X / 1-2x-x = - X / [- (x? + 2x-1)] = x / (x? + 2x-1)
(2) - (3y-7y squared) / (5-7y + y squared)
=(7y²-3y)/(y²-7y+5)

When x is taken, the value of this fraction is 0

simple form
=(x + 2) (X-2) of X (x + 2)
 
From the meaning of the title:
（x+2）（x-2）≠0
x（x+2）=0
 
The solution is as follows:
X ≠ - 2 or 2
X = 0 or - 2
 
So: x = 0
 

1、 If the value of molecule x (x-3) / x 2 + 2 is 0, then the value of fraction 2x / x? - 1 divided by 2x / 1-x is 0_________ . 2、 If x is equal to its reciprocal, then the value of fraction x? 2 + 2x-3 / X-1 divided by X + 2 / x? - 3x + 1 is_________ (3) given that / A-4 / + √ B-9 = 0, find a? + AB / b? Multiplied by a? - AB / a? - B

If [x (x-3)] / (x ^ 2 + 2) = 0, the solution is as follows:
∵x(x-3)/(x^2+2)=0
∴x(x-3)=0
The solution is: x = 0, x = 3
When x = 0, [2x / (x ^ 2-1)] / [2x / (1-x)] has no solution
When x = 3, [2x / (x ^ 2-1)] / [2x / (1-x)] = - 1 / (x + 1)
=-1/4
If x = 1 / x, then x = 1
∴x-1=0
ν [(x ^ 2 + 2x-3) / [(x + 2) / (x ^ 2-3x + 1)] has no solution
The last problem, known conditions do not understand

If the value of fraction x? - 4 / 2x? - 5x + 2 is zero, can you find the value of X 2X 2 - 5x + 2 / x 2 - 4

2X 2 - 5x + 2 / x 2 - 4
=(x+2)(x-2)/(2x-1)(x-2)
=(x+2)/(2x-1)=0;
∴x=-2;
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Simplify the 2 - 2x of X of fraction 2Y XY

(x²-2x)/(2y-xy)
=x(x-2)/y(2-x)
=-x/y
If you do not understand, please ask, I wish you a happy study!

If 2x = - y, then fraction (XY) / (x? - y?)=_____

That is, y = - 2x
So y 2 = 4x
xy=-2x²
So the original formula = - 2x? /) x? - 4x?)
=-2x²/(-3x²)
=2/3

The fraction x? Y? Y / xy-xy-y? / xy-x? Can be reduced to ()

The original formula = (x? - y?) / xy-y (X-Y) / [- x (X-Y)]
=(x²-y²)/xy+y/x
=(x²-y²+y²)/xy
=x²/xy
=x/y

If x / y = 3 / 2, then the value of fraction (2x? - XY) / XY is

(2x²-xy)/xy
Divide the numerator and denominator by Y 2 at the same time
2[(x/y)²-(x/y)]/(x/y)
=2×[(3/2)²-(3/2)]/(3/2)
=2×(9/4-3/2)/(3/2)
=2×(3/2)/(3/2)
=2

The fraction (x? Y? XY) - (xy-y? Xy-x?) can be reduced to

The original formula = (x 2 - y 2) / XY + y (X-Y) / X (X-Y)
=(x²-y²)/xy+y/x
=(x²-y²+y²)/xy
=x²/xy
=x/y

The difference between X + 1 and 1 / 2x is equal to the fraction 2x + 1 / 2. Find the value of X

The common factor (x + 1) can be reduced directly, i.e. 1 / (x-1)
The left side of the equation is divided into (x + 1) / 2x (x-1). The right side of the equation is still 1 / (2x + 2)
By solving the equation, 2 (x + 1) 2 = 2x (x-1), we get 3x = - 1, x = - 1 / 3