Question

\(\left(x-5\right)\left(-x+4\right)-\left(x-1\right)\left(x+3\right)=2x^2\)

Answer 1

\(\Leftrightarrow-x^2+4x+5x-20-\left(x^2+2x-3\right)=2x^2\)

\(\Leftrightarrow2x^2=-x^2+9x-20-x^2-2x+3=-2x^2+7x-17\)

\(\Leftrightarrow4x^2-7x+17=0\)

hay \(x\in\varnothing\)

Answer 2

\(-x^2+4x+5x-20-x^2-3x+x+3-2x^2=0\)

\(-4x^2+7x-17=0\)

Ptr vô nghiệm

Answer 3

`(x-5)(-x+4)-(x-1)(x+3) =2x^2`

`<=>-x^2 +4x+5x-20-(x^2+3x-x-3) = 2x^2`

`<=> -x^2 +4x+5x-20-x^2 -3x+x+3 -2x^2 =0`

`<=> 4x^2 -7x+17=0`

`=> Delta = (-7)^2 -4*4*17 = -223 <0`

`=> PT (vô . nghiệm)`