Question

1 2
____ = ___
c+5 3

Answer 1

are you familiar with proportions ?

Answer 2

Mostly, yes.

Answer 3

what you have here is a proportion, and to solve this, you must cross multiply.
1/(c + 5) = 2/3
cross multiply
2(c + 5) = (1)(3)
can you take it from here and solve for c. Don't forget to distribute through the parenthesis.

Answer 4

2c + 10 = 3
2c = 3 - 10
2c = -7
c = -7/2

check.
1/(c + 5) = 2/3
1/(-7/2 + 5) = 2/3
1/(-7/2 + 10/2) = 2/3
1/(3/2) = 2/3
1 * 2/3 = 2/3
2/3 = 2/3 (correct)

c = -7/2

any questions ?

Answer 5

I understand. Thanks a ton :D