# Find f(5) if f(x)= …

“Find f(5) if $f(x)=x^2-3x$

Solving:

$f(5)=(5)^{2}-3(5)$

Expand the exponent (2) to the expression.
Squaring a number is the same as multiplying the number by itself (5*5). In this case, 5 squared is 25.
f(5)=(25)-3(5)

Multiply -3 by each term inside the parentheses.
f(5)=25-15

Subtract 15 from 25 to get 10.
f(5)=10