Question:
Find the value of the expression (9x2 + 24x + 16), when x = 12.
Solution:
$\left(9 x^{2}+24 x+16\right)$
Given, $x=12$
$\Rightarrow(3 x)^{2}+2(3 x)(4)+(4)^{2}$
$\Rightarrow(3 x+4)^{2}$
$\Rightarrow(3(12)+4)^{2}$
$\Rightarrow(36+4)^{2}$
$\Rightarrow(40)^{2}=1600$
Therefore, the value of the expression (9x2 + 24x + 16), when x = 12, is 1600.