Answer:
Part 19) x=5
Part 20) x=-3
Explanation:
Problem 19) Find the value of x so that f(x)=7
step 1
Find the intersection point of the given line in the graph with the line y=7
The intersection point is (5,7)
see the attached figure
therefore
The x-coordinate of the intersection point is the value of x when f(x)=7
x=5
f(5)=7
Problem 20) Find the value of x so that f(x)=7
step 1
Find the intersection point of the given line in the graph with the line y=7
The intersection point is (-3,7)
see the attached figure
therefore
The x-coordinate of the intersection point is the value of x when f(x)=7
x=-3
f(-3)=7