Rational expression

Question

Consider the following situation. If a number is added to the numerator of 5/7 and the same number is subtracted from the denominator, the result is 3. Let x represent the unknown number. Write an equation in terms of x that represents the given situation.

Answer 1

(5+x)/(7-x) = 3

5+x = 21-3x

4x = 16

x = 4

(5+4)/(7-4) = 9/3 = 3