Question

How to use the proper formula

Answer 1

Just plugin -3 where the x is in $2x^2 - x$
$f(-3) = 2x^2 - x$
$f(-3) = 2(-3)^2 - (-3)$
$f(-3) = 2(9) - (-3)$
$f(-3)= 18 - (-3)$
$f(-3) = 21$
$21$ <------The answer

Answer 2

21 is the answer
thanks (: