Question

Find the value of the expression $3x(4x-5)+3$ for $x=3$.

Answer 1

Let,

$f\left(x\right)=$ $3x(4x-5)+3$

or, $f\left(x\right)=12x^2-15x+3$.

Then,

$f\left(3\right)$ $=12\times 9-15\times 3+3$

$=108-45+3$

$=66$