Question

Simplify $3x(4x-5)+3$ and find the value for the given expression at $x=3$.

Answer 1

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

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

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

$=12x(x-1)-3(x-1)$

$=(12x-3)(x-1)$

$=3(4x-1)(x-1)$

$\Rightarrow$ Value $x=3,$ then $3(4x-1)(x-1)=3(12-1)(3-1)$

$=66$

Hence, the answer is $66.$