help me pls mn ui ;-;

Bài 1 :

a) 5x²y : xy -2x² + 10

⇔ -2x²+5x+10

b) 2x(3x+2)+(4x+3)(2x-1)

⇔ 6x² + 4x + 8x² -4x +6x -3 

⇔ 14x²+6x-3

c) (x+2)²- (x+5)(x-5)

= x² +4x+4- (x²-5²)

=x²+4x+4-x²+25

=4x+29

d) (4x+5)² - (8x+10)(1-3x) + (1-3x)²

⇔ (4x+5)² - 2(4x+5)(1-3x) + (1-3x)²

⇔ (4x+5-1+3x)²

⇔(7x+4)²

Bài 2 :

a) 8x²+16xy

⇔8x(x+2y)

b) 3(x+12)-x²-12x

⇔ 3(x+12)-x(x+12)

⇔(x+12)(3-x)

c) x²-6x-z²+9

⇔ (x-3)²-z²

⇔ (x-3+z)(x-3-z)

d) x²-2x-15

⇔ x²-2x+1-16

⇔ (x-1)²-4²

⇔ (x-5)(x+3)

Bài 3 :

a) x(x+4)-x²=10

⇔ x²+4x-x²+10=0

⇔2(2x+5)=0

⇔2x+5=0

⇔ x= - $\frac{5}{2}$ 

b) 5x²+2x=0

⇔ x(5x+2)=0

⇒ x=0  hoặc 5x+2=0

⇔x=0 hoặc x= - $\frac{2}{5}$ 

c) x²-16=x+4

⇔ (x-4)(x+4)-(x+4)=0

⇔ (x+4)(x-4-1)=0

⇔ (x+4)(x-5)=0

⇒ x+4=0  hoặc x-5=0

⇔ x=-4  hoặc x=5

d) (4x-1)²-(x+7)²=0

⇔ (4x-1+x+7)(4x-1-x-7)=0

⇔(5x+6)(3x-8)=0

⇒ 5x+6=0  hoặc  3x-8=0

⇔x= - $\frac{6}{5}$ hoặc  x= $\frac{8}{3}$

5 sao nha