Standard showerhead in andrew's house dispenses 8 gallons of water per minute. andrew changed this shower head to an energy-saving one. the equation shows the amount of water dispensed, y, as a function of the number of minutes, x, for the new shower head.
y = 3x
how much water does andrew save each day with the change in shower heads if he uses the shower for 8 minutes each day?
5 gallons
16 gallons
24 gallons
40 gallons

Slope is the rate of change.
y=3x.
3 is the slope here, and it means that the new shower head dispenses 3 gallons per minute.
Following, this pattern, the equation for the previous shower head is y=8x.
From this point, there are two ways to solve this:
Way 1: Input x, which in this case is 8 minutes, into each equation, and then find the difference with subtraction.
y=3x
y=3*8
y=24
So the new shower head dispenses 24 gallons in eight minutes.
y=8x
y=8*8
y=64
Therefore, you can conclude that the old shower head dispensed 64 gallons in eight minutes.
To figure out how much he saves, subtract the values:
64-24= 40 gallons.
Way 2) Find the difference before substitution:
y=8x-3x
y=5x
Substitute for x.
y=5*8
y=40 gallons
Therefore, the answer is D. 40 gallons. I hope this helped :)