Answer:

Step-by-step explanation:

Let's solve the second equation for a to later on replace it in the first equation.

Now plug this into the first equation.

Distribute the 9

Break down the fraction.

Simplify.

Subtract 

Combine like terms.



Muliply by the reciprocal or inverted fraction next to b.


Now plug this value into any of the equations to find the value of a.

I think 51 because if you were to do it reverse then it would be 40x4=160 then -35-36-38 it would be 51.
If the equation for volume is V=l*w*h, you can plug in all of the information you know. When you do this, the equation becomes 1440=15*12*h, or 1440=180*h (because 15*12=180). You can divide both sides by 180 to get h. 1440/180=8, do the depth of the pool is 8 ft. You can also check this answer by making sure that 15*12*8 is equal to 1440 (which it is). I hope this helped!