b. x²-7x+6=0

=>x²-x-6x+6=0

=> x(x-1)-6(x-1)=0

=>(x-6)(x-1)=0

=>x-6=0 hoặc x-1=0

=>x=6 hoặc x=1

bài 1

a(x+y)²-(x-y)²

=[(x+y)-(x-y)][(x+y)+(x-y)]

=(x+y-x+y)(x+y+x-y)

=2y.2x

b,(3x+1)²-(x+1)²

=[(3x+1)-(x+1)][(3x+1)+(x+1)]

=(3x+1-x-1)(3x+1+x+1)

=2x.(4x+2)

4x.(x+10

x(3x-2)-5(2-3x)=0

=>x(3x-2)+5(3x-2)=0

=>(3x-2)(x+5)=0

=>3x-2=0 hoặc x+5=0

=>3x=2 hoặc x=-5

=>x=\(\dfrac{2}{3}\)

vậy x= \(\dfrac{2}{3}\) hoặc -5

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