
Hmmm... Strange very very strange. The bars around the w represent absolute value, and whatever is inside those bars always yields a positive answer. So, |-87| = 87 or |-8| = 8 or even |5|=5
Answer:
Part 19) x=5
Part 20) x=-3
Step-by-step 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
For this case we have the following expression:

We multiply both sides by: 

We divide both sides by 216:

To divide powers of the same base, we place the same base and subtract the exponents:

Rewriting:

To multiply powers of the same base, we place the same base and add the exponents:

We know that any number raised to zero is 1, 
So, for equality to be true:

Answer:

just count how many there and and eliminate one by one