Question

Help me

Answer 1

Bài 3: 

a) Ta có: \(2x\left(x-5\right)-x\left(2x+3\right)=26\)

\(\Leftrightarrow2x^2-10x-2x^2-3x=26\)

\(\Leftrightarrow-13x=26\)

hay x=-2

Vậy: S={-2}

b) Ta có: \(\left(3x^2-x+1\right)\left(x-1\right)+x^2\left(4-3x\right)=\dfrac{5}{2}\)

\(\Leftrightarrow3x^3-3x^2-x^2+x+x-1+4x^2-3x^3=\dfrac{5}{2}\)

\(\Leftrightarrow2x=\dfrac{7}{2}\)
hay \(x=\dfrac{7}{4}\)

Vậy: \(S=\left\{\dfrac{7}{4}\right\}\)