For each value of x, determine whether it is a solution to 21 = 3x +9.
Is it a solution?
Yes
No
-8.

No

Step-by-step explanation:

If you plug in a -8 into 21=3x+9 you get

21= -15 which is not true

1 number

if we use a graphing calculator, there is only one such number that satisfies the conclusion of the mean value theorem, that is, a number such that

where the right-hand side is the average rate of change of f on the interval [0.5,0.75], which is the slope of the secant line.

in the attached graph, the black line is the secant line which has its slope as the average rate of change of f on [0.5,0.75], while the orange line is the only tangent line to the graph of f in the interval that satisfies the mvt conclusion.