Question

chung minh bieu thua sau co gia trin duong voi moi x

a)x^2-x+1

b)(x-2)(x+4)

c 2x^2-4xy+4y^2+2x

Answer 1

a: \(=x^2-x+\dfrac{1}{4}+\dfrac{3}{4}=\left(x-\dfrac{1}{2}\right)^2+\dfrac{3}{4}>0\)

b: \(=x^2+2x-8\)

\(=x^2+2x+1-9=\left(x+1\right)^2-9>=-9\)