Question

1. Tính
a) \(\left(x+2y\right)^2\)
b) \(\left(x-3\right)\left(x+3\right)\)
c) \(5-x^2\)
d) \(\left(x-1\right)^2\)
e) \(\left(3-y\right)^2\)
2. Rút gọn
a) \(\left(x+y\right)^2+\left(x-y\right)^2\)
b) \(2\left(x-y\right)\left(x-y\right)+\left(x+y\right)\left(x-y\right)\)
c) \(\left(x-y+z\right)^2+\left(z-y\right)+2\left(x-y+z\right)\left(y-z\right)\)

Answer 1

Bài 1: 

a: \(=x^2+4xy+4y^2\)

b: \(=x^2-9\)

c: \(=\left(\sqrt{5}-x\right)\cdot\left(\sqrt{5}+x\right)\)

d: \(=x^2-2x+1\)

e: \(=y^2-6y+9\)

Answer 2