College algebra: Solve n = (5000x - 33400)/7 for c

[peaceful4]

Please show how to solve this problem.

A monthly water bill in a certain city is calculated by using the formula :

. . .n = (5000c - 33400) / 7

...where "n" is the number of gallons and "c" is the monthly cost. Solve for c and compute the bill for the quantity of 1300 gallons.

 

[jonboy]

A monthly water bill in a certain city is calculated by using the formula :

. . .n = (5000c - 33400) / 7

...where "n" is the number of gallons and "c" is the monthly cost. Solve for c and compute the bill for the quantity of 1300 gallons.

Well this might be college but I am in 9th grade and can solve this! :shock: :wink:


\(\displaystyle \L n\,=\,\frac{5,000c\, - \, 33, 400}{7}\)



.........Fill in what we know: \(\displaystyle \L \;1,300\,=\,\frac{5,000c\, - \, 33, 400}{7}\)


\(\displaystyle \L \;7(1,300)\,=\,(\frac{5,000c\, - \, 33, 400}{7})7\,\to\,9,100\,=\,5,000c\, - \, 33,400\)


........Addition Property: \(\displaystyle \L \;\,42,500\,=\,5,000c\to\,c\,\approx\,$8.50\)



Check: \(\displaystyle \L \;1,300\,=\,\frac{5,000(8.5)\,-\,33,400}{7}\,\to\,1,300 \,=\,1,300\)

There you go!