(3x+1)+(2x+4)=90
3x+1+2x+4=90
5x+5=90
5x=85
x=17
Answer:
Step-by-step explanation:

Answer:
The y-intercept is 0, which represents the amount of gas used when 0 miles are traveled. The slope is 28, which represents the miles that can be traveled with 1 gallon of gas
Step-by-step explanation:
Let
x----> the amount of gas used in gallons
y ---> the distance traveled in miles
we have

This linear equation represent a direct variation
The y-intercept is the value of y when the value of x is equal to zero
For x=0, y=0
That means ----> The y-intercept is 0, which represents the amount of gas used when 0 miles are traveled
The slope is 
That means ----> The slope is 28, which represents the miles that can be traveled with 1 gallon of gas