Question

You are trying to use lesswater on laundry this month than you used on laundrylast month. The amount of water w (in gallons)you save after x loads of laundry is given byw(x) = 160 - 20x. How many loads of laundry didhis month if you saved 40 gallons of water?

Answer 1

Given:

`w\left(x\right)=160-20x`

Where:

w (x) = amount of water you save

x = loads of laundry

Knowing that you saved 40 gallons, then w (x) = 40.

Let's substitute w(x) by 40 and find x.

`40=160-20x`

Subtracting 160 from both sides of the equation:

`\begin{gathered} 40-160=160-20x-160 \\ -120=160-160-20x \\ -120=0-20x \\ -120=-20x \end{gathered}`

Dividing both sides by -20:

`\begin{gathered} (-120)/(-20)=(-20x)/(-20) \\ 6=x \\ x=6 \end{gathered}`

Answer: 6 loads of laundry.