Question

Rút gọn biểu thức:

a,A=(x - y + z)² + ( z - y )² + 2(x - y + z)(y - z)

b,B=(5x -1) + 2(1-5x)(4 + 5x) + ( 5x + 4)²

c,C=(x - y )³ + ( y+ x)³ + ( y - x)³ - 3xy( x + y)

Answer 1

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