Question

How do I solve for r

Answer 1

To solve for R you use PEMDAS

Answer 2

4 (r-10)^2+2=38
expand 4 [(r-10)(r-10)]+2=38
solve r-10×r-10
4 (r^2-20r+100)+2=38
-2 both sides
4 (r^2-20r+100)=36
÷4 both sides
r^2-20r+100=9
-9 both sides
r^2-20r+91=0
(r-7)(r-13)=0
r=7,13