Answer:
hours
Step-by-step explanation:
Let x be the time ( in hours ) you feel good and y be the time ( in hours ) that you get tired.
As per given , we have
x+y= 8
Since : 
So , we have
20x+12y=122
According to the given question , we have the following system of equations ,

Multiply 12 on both sides of equation (1) , we get

Eliminate equation (3) from (2) , we get

Hence, you felt
hours good.
Answer:
x=-1
Step-by-step explanation:
The lines stand for absolute value ( how far a number is from 0), so each number should be a positive, then you just solve for x. Isolate x, then divide on both sides, and you should get -x=1, which is equal to x=-1.
Answer:
One of the negatives must go
Step-by-step explanation: