Answer:
Solutions Below.
Step-by-step explanation:
These questions test on the concept of Functions Substitution.
Function Substitution
Function Substitution is about giving an input (domain) to a function to produce an output (range)
Example: f(x) = 9x , f(9) = 9(9) = 81
Application
We are given the following function:
f(x) = 10x + 8, where we can express it as
y = 10x + 8
Now we can find the value of f(5) by substituting x = 5 into the function. (Meaning: Find the value of y when x = 5.)
f(5) = y = 10(5) + 8 = 50 + 8 = 58
Next, applying the same concept, we can find the value of f(-7) by substituting x = - 7 into the function. (Meaning: Find the value of y when x = -7.)
f(-7) = y = 10(-7) + 8 = -70 + 8 = - 62
This last question requires us to work in reverse, where we find the value of x when f(x) = y = 88.
f(x) = y = 10x + 8
10x + 8 = 88
10x = 88 - 8
10x = 80
x = 80 ÷ 10 = 8
