Question

\(9x^2-30x+225=0\)

Answer 1

`9x^2-30x+225=0`

`<=>3x^2-10x+75=0`

<=>2x^2-10x+25+x^2+50=0`

`<=>2(x-5/2)^2+x^2+50+25/2=0`

Vì `2(x-5/2)^2+x^2>=0`

`=>2(x-5/2)^2+x^2+50+25/2>=50+25/2>0`

Vậy PT vô nghiêm

Answer 2

Lag nhẹ

`9x^2-30x+225=0`

`<=>3x^2-10x+75=0`

`<=>2x^2-10x+25+x^2+50=0`

`<=>2(x-5/2)^2+x^2+50+25/2=0`

Vì `2(x-5/2)^2+x^2>=0`

`=>2(x-5/2)^2+x^2+50+25/2>=50+25/2>0`

Vậy PT vô nghiêm