#### Answer

$12$

#### Work Step by Step

Substitute $8$ in for $x$ to obtain:
$=8^2-7\cdot 8 +4$
Apply the exponent first to obtain:
$=64-7\cdot 8+4$
Perform multiplication next:
$=64-56 + 4$
Perform subtract first and then addition:
$=8 + 4
\\=12$