Question

1)phân tích các đa thức thành nhân tử

a) 7x²-7xy-4x+4y

b) 2x-2y+ax-ay

c) x²-x-y²-y

d) ax+ay-2x-2y

e) x(a+b)-a-b

Answer 1

\(a,7x^2-7xy-4x+4y\)

\(=7x\left(x-y\right)-4\left(x-y\right)\)

\(=\left(7x-4\right)\left(x-y\right)\)

\(b,2x-2y+ax-ay\)

\(=2\left(x-y\right)+a\left(x-y\right)\)

\(=\left(a+2\right)\left(x-y\right)\)

\(c,x^2-x-y^2-y\)

\(=\left(x^2-y^2\right)-\left(x+y\right)\)

\(=\left(x+y\right)\left(x-y\right)-\left(x+y\right)\)

\(=\left(x+y\right)\left(x-y-1\right)\)

\(d,ax+ay-2x-2y\)

\(=a\left(x+y\right)-2\left(x+y\right)\)

\(=\left(a-2\right)\left(x+y\right)\)

\(e,x\left(a+b\right)-a-b=x\left(a+b\right)-\left(a+b\right)\)

\(=\left(x-1\right)\left(a+b\right)\)