If f(x)=x^2-3x,find f(-18). Show work
Mathematics · High School · Tue Nov 03 2020
Answered on
Given the quadratic function:
f(x) = x^2 - 3x
Find f(-18)
Solution:
In order to find f(-18) simply substitute -18 in all the values of x in the given quadratic function.
f(x) = x^2 - 3x
f(-18) = (-18)^2 - 3(-18)
f(-18) = (324) - (-54)
The negative signs will become positive, since similar signs will result a positive sign, while opposite signs will result a negative sign.
f(-18) = 324 + 54
f(-18) = 378