Question

1,phân tích đa thức thành nhân tử

a,\(^{x^2-2x+2y-xy}\)

b,\(\left(x^2+1\right)^2-4x^2\)

2,tìm x,biết:

\(x\left(3x+2\right)+\left(x+1\right)^2-\left(2x-5\right)\left(2x+5\right)=-12\)

giúp mk vs mai nộp rùi hu hu

Answer 1

1

a . X.(X-2)-Y.(X-2)=(X-Y).(X-2)

b .(X² +1+2X).(X² +1-2X)

2

3X² +2X+X² +2X+1-4X² -10X+10X+5=(-12)

4X+6= -12

X=9/2

Answer 2

1. a, x²-2x+2y-xy = x(x-2)+y(2-y) = x(x-2)-y(x-2) = (x-y)(x-2)

b, (x²+1)²-4x² = (x²+1-2x)(x²+1+2x) = (x-1)²(x+1)²

2. x(3x+2)+(x+1)²-(2x-5)(2x+5) = -12

=> (3x²+2x+x²+2x+1)-(2x)²-5² = -12

_{=> 3x²+2x+x²+2x+1-4x²-25 = -12}

_{=> 4x-24 = -12 => 4x = 12 => x = 3}

 

Answer 3

2, \(x\left(3x+2\right)+\left(x+1\right)^2-\left(2x-5\right)\left(2x+5\right)=-12\)

<=> \(3x^2+2x+x^2+2x+1-4x^2-10x+10x+25=-12\)

<=> \(4x+26=-12\)

<=> \(4x=-12-26=-38\)

<=> \(x=-38:4=\frac{-19}{2}\)

vậy x=\(\frac{-19}{2}\)

Answer 4

1.a. X² - 2x + 2y - xy

= ( X² - xy ) - ( 2x - 2y )
= x ( x-y) - 2.(x-y)
=(x-y).(x-2)
b. ( x²+ 1)²-4x²
=(x²+1)²- (2x)²
=(x² + 1 - 2x).(X²+1+2x)
2. x.(3x+2)+(x +1 )²-(2x-5).(2x+5)=3x²+2x+x²+2x+1-4x²+25=-12

( 3x²+x²-4x²)+(2x+2x)+(1+25)=-12
4x+26=-12 Suy ra 4x=-38 Suy ra x=-9.5