Question

\(\text{Rút gọn:}\)

\(a.\left(x-y+z\right)^2+\left(z-y\right)^2+\left(x-y+z\right)\left(2y-2z\right)\)

\(b.\left(a+b\right)\left(a^2-ab+b^2\right)-\left(a-b\right)\left(a^2+ab+b^2\right)\)
 

Answer 1

Câu B tương tự nha :

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

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

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

\(=x^2\)

Answer 2

câu b nha  ( a + b )( a ^ 2 - ab + b ^ 2 ) -( a - b )( a ^ 2 + ab + b ^ 2 ) = (a^3 - a^2 * b + ab^2 + ba^2 - ab^2 + b^3)  - (a^3 + a^2 * b + ab^2  - a^2 * b - ab^2 - b^3) = (a^3 + b^3 ) - (a^3 - b^3) = 2b^3