Question

Phân tích thành nhân tử:

a) 5 . (x - y) - y . (x - y)

b) y . (x - 2) + 7 . (2 - x)

c) 27^2 - (y-1) - 9x^3 . (1 - y)

d) 4x . (x - 2016 - x + 2016)

e) (2x - 1)^3 - 2x + 1

f) (7x - 4) - (2x + 1)^2

m) 25 - (3 - x)^2

n) (x - 5)^2=16

Answer 1

a) 5.(x-y)-y(x-y)

= (x-y)(5-y)

b) y.(x-2)+7(2-x)

= y.(x-2) -7(x-2)

=(x-2)(y-7)

c) sửa lại đề

27².(y-1) -9x³(1-y)

=27².(y-1) + 9x³(y-1)

= (y-1)(27²+9x³)

d) 4x(x-2016-x+2016)

= 4x.0

= 0

e) (2x-1)³ - 2x+1

= (2x-1)³ - (2x-1)

= (2x-1)[(2x-1)²-1]

=(2x-1)(2x-1-1)(2x-1+1)

=2x.(2x-1)(2x-2)

=4x.(x-1)(2-1)

m) 25-(3-x)²

= [5-(3-x)][5+(3-x)]

=(5-3+x)(5+3-x)

n) (x-5)²=16

=> (x-5)²=4² hoặc (x-5)²=(-4)²

=> (x-5)=4 hoặc x-5=-4

trường hợp 1

x-5=4

x= 4+5

x=9

trường hợp 2

x-5=-4

x=-4+5

x=1

vậy x=9 hoặc x=1

Answer 2

a) \(5.\left(x-y\right)-y.\left(x-y\right)=\left(x-y\right)\left(5-y\right)\)

b) \(y.\left(x-2\right)+7.\left(2-x\right)=\left(x-2\right)\left(y+7\right)\)