Question

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

Answer 1

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

$i).$ If $x=3$

$=3\times 3(4\times 3-5)+3$

$=9(12-5)+3$

$=9\times 7+3$

$=66$

$ii).$ If $x=\frac{1}{2}$

$=\frac{3}{2}(\frac{4}{2}-5)+3$

$=\frac{3}{2}(-3)+3$

$=\frac{-9}{2}+3$

$=\frac{-9+6}{2}$

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

Hence, solved.