Ur output value is f(x).....so to do this problem u need to sub in 2/3 for f(x) and solve for the input value which is x
f(x) = -1/3x + 7
2/3 = -1/3x + 7 ...multiply everything by 3
2 = -x + 21
2 - 21 = - x
- 19 = -x
19 = x <== ur output
2
Divide both the top and bottom by 2 and you get 2/3
Answer: 6.35444444×10^13 gallons
Step-by-step explanation:
So a dishwasher uses 444 gallons of water per load.
That means it'll use 444*215215215 = 95555555460 gallons of water for 215215215 loads
Since washing dishes by hand takes 666 as much as water in comparison to using a dishwasher, we can do 95555555460x666 to find that you need 6.36399999×10^13 gallons of water to wash 215215215 loads.
The question asks for how much more water in gallons you can save, so do 6.36399999×10^13 - 95555555460 to get 6.35444444×10^13 gallons