Let x and y represent the numbers of gallons used by the 40 mpg and 35 mpg cars, respectively.
.. x +y = 40 . . . . . . . . . . .total consumption is 40 gallons
.. 40x +35y = 1525 . . . . total miles driven = 1525
Multiply the first equation by 40 and subtract the second.
.. 40(x +y) -(40x +35y) = 40(40) -(1525)
.. 5y = 75
.. y = 15
.. x = 40 -15 = 25
The 40 mpg car consumed 25 gallons.
The 35 mpg car consumed 15 gallons.
45 is exactly half of 90
that means 45 is 50% of 90.
Answer:
y = 3x + 7
Step-by-step explanation:
First, we will solve for the slope (m).
The formula for slope is: m = 
m =
--- enter the points into the formula
m =
--- simplify
m = 3 --- simplify
Now we will solve for the y-intercept (b).
y = mx + b
y = 3x + b --- substitute the slope into the equation
-20 = 3(-9) + b --- substitute the x and y of either point into the equation
-20 = -27 + b --- simplify
7 = b --- add 27 to both sides
b = 7
Done.
y = 3x + 7