The table shows a linear function :)
A. 18+2 = 20 abs 18-2= 17
X^2 + 9 + 7 = 20
X^2 +16 = 20
X^2 = 20-16
X^2 = 4
Root 4 = 2
X=2
f(x) = -10
set the equation equal to -10 and solve for x:
-10 = -x-1
Add 1 to both sides:
-9 = -x
Divide both sides by -1:
x = 9
