Answer:
C would be equal to (f - 13)/(10 - d)
Step-by-step explanation:
In order to find this, you must manipulate the equation so that the left side has every term with a c in it. Then you can isolate it by dividing and find what it is equal to.
10c - f = -13 + cd -----> Add f to both sides
10c = f - 13 + cd -----> Subtract cd from both sides
10c - cd = f - 13 ------> Pull out c
c(10 - d) = f - 13 -----> Divide by (10 - d)
c = (f - 13)/(10 - d)
