To find c, you must isolate it.
To do this, you must divide both sides by 5/7, since that is being multiplied by c and you must do the inverse to it to cancel it out in order to leave c by itself.
5/7c ÷ 5/7 = c
13/14 ÷ 5/7
To divide fractions, follow these steps:
Step 1- Turn the second fraction, 5/7 in this case, into its reciprocal. This means swapping the places of the numerator and denominator.
5/7 reciprocal = 7/5
Step 2- multiply the original first fraction and reciprocal second fraction.
13/14 • 7/5
13 • 7 = 91
14 • 5 = 70
13/14 ÷ 5/7 = 91/70
Step 3- Simplify if possible.
91/70
Since 70 can go into 90, you can turn this into a mixed number.
1 and 21/70
Now simplify 21/70.
Both can be divided by 7.
21 ÷ 7 = 3
70 ÷ 7 = 10
So simplified, 91/70 equals 1 and 3/10.
As a decimal, this is 1.3.
So the answer is c = 1.3, or 1 and 3/10.
Hope this helps :)