Question

If $4a-3=13,$ then find the value of $10a^2-5a+6.$

Answer 1

$\begin{array}{cc}4a-3& =13\\ 4a& =13+3\\ & =16\\ a& =4\end{array}$

Let,

$p\left(a\right)=10a^2-5a+6$

Substitute $4$ for $a$ in $p\left(a\right),$

$\begin{array}{cc}p\left(4\right)& =10{\left(4\right)}^2-5\left(4\right)+6\\ & =10\left(16\right)-20+6\\ & =160-20+6\\ & =146\end{array}$