$50
20 x 2 = 40, which is 80%
and then 20 divided by 2 is 10; so you add that to 40 and you get your answer
Answer:

Step-by-step explanation:
we know that
The algebraic expression is equal to

Remember that

and

so

substitute

The rate of change is the slope.
f(x) is the same as y...
f(x) = 3x + 9.....y = 3x + 9....and in y = mx + b form, the rate of change(slope) can be found in the m position.
y = mx + b
y = 3x + 9....so the slope or rate of change is 3...not 9...so answer is false