Question

rút gọn biểu thức :

a,[x+y]^2.[x-y]^2

b,2.[x-y][x+y]+[x+y]^2+[x-y]^2

c,[x-y+z]^2+[z-y]^2+2.[x-y+z][y-z]

Answer 1

a,[x+y]^2.[x-y]^2=x⁴-2x²y²+y⁴

b,2.[x-y][x+y]+[x+y]^2+[x-y]^2=4x²

c,[x-y+z]^2+[z-y]^2+2.[x-y+z][y-z] (x - y + z)² + (z - y)² + 2(x - y + z)(y - z)
= (x - y + z)² + 2(x - y + z)(y - z) + (y - z)²
= (x - y + z + y - z)²
= x²

Câu c mk thấy khó nên viết luôn cách giải nha

Answer 2

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

b) \(2\left(x-y\right)\left(x+y\right)+\left(x+y\right)^2+\left(x-y\right)^2=\left(x+y+x-y\right)^2=\left(2x\right)^2=4x^2\)

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

(Lấy y-z chứ không được lấy z-y)