-4r-11=4r+21
Move 4r to the other side
Sign changes from +4r to -4r
-4r-4r-11=4r-4r+21
-4r-4r-11=21
-8r-11=21
Move -11 to the other side
Sign changes from -11 to +11
-8r-11+11=21+11
-8r=21+11
-8r=32
Divide both sides by -8
-8r/-8=32/-8
Answer: r=-4
Use the formula T(x) = 0.01x2^x
X is the number of days.
T(8) = 0.01 x 2^8
T(8) = 0.01 x 256
T(8) = $2.56
It does show a function because it passes the vertical line test (no two points have the same x value).
