Question

Tính : 

a) ( x - 2y )( 3xy + 6y^2 + x )

b) [ 4 ( x-y )^5 + 2( x - y )^3 - 3( x - y )^2 ] : ( y - x )^2

Answer 1

a)\(\left(x-2y\right)\left(3xy+6y^2+x\right)=x\left(3xy+6y^2+x\right)-2y\left(3xy+6y^2+x\right)\)\(=3x^2y+6xy^2+x^2-6xy^2-12y^3-2xy\)

\(=3x^2y+x^2-12y^3-2xy\)

b)\(\text{[}4\left(x-y\right)^5+2\left(x-y\right)^3-3\left(x-y\right)^2\text{]}:\left(y-x\right)^2\)

=\(\text{[}4\left(x-y\right)^5+2\left(x-y\right)^3-3\left(x-y\right)^2\text{]}:\left(x-y\right)^2\)

=\(^{=4\left(x-y\right)^3+2\left(x-y\right)-3}\)