Answer
$10$
Work Step by Step
Substitute $7$ for $x$ to obtain:
$=7^2-6\cdot 7 +3$
Apply the exponent first to obtain:
$=49-6\cdot 7+3$
Perform multiplication next:
$=49-42 + 3$
Perform subtract first and then addition:
$=7 + 3
\\=10$