Question

Simplify $3x(4x-5)+3$ and find its value $x=\frac{1}{2}$.

Answer 1

$3x(4x-5)+3=3x-4x-3x.5+3$

$=12x^2-15x+3$

For $x=\frac{1}{2}$ , the value is $12\left(\frac{1}{4}\right)-15\left(\frac{1}{2}\right)+3$

$=3-\frac{15}{2}+3$

$=6-\frac{15}{2}$

$=\frac{-3}{2}$