Answer:
Nifal received $ 4 for washing the first car.
Nifal received $ 5 for washing the second car.
4 and 5 have a sum of 9.
Step-by-step explanation:
The problem can be rewritten as follows: Find the sum of two consecutive entire numbers equal to 9. That is:


Then, by eliminating y:

Now, let is clear
:


Nifal received $ 4 for washing the first car.
The earning for the second car is: (
)



Nifal received $ 5 for washing the second car.
4 and 5 have a sum of 9.
Just substitute in the number 3 for x then subtract 3 at both sides and youll have y=7
Equation y=-4x
m=-4. Slope is -4 y-intercept is 0
y-12=2(x-1)
y-12=2x-2
y=2x-2+12
y=2x+10