Question

How to solve 1/x + 1/4 =7/12

Answer 1

1/x + 1/4 = 7/12
1/x = 7/12 - 1/4
1/x = 7/12 - 3/12
1/x = 1/3....multiply both sides by x
1 = 1/3x
1 / (1/3) = x
1 * 3/1 = x
3 = x <====

Answer 2

You need a common denominator for addition/subtraction

$\frac{1}{x} = \frac{7}{12} - \frac{1}{4} ( \frac{3}{3} ) \\ \\ \frac{1}{x} = \frac{7}{12} - \frac{3}{12} \\ \\ \frac{1}{x} = \frac{4}{12} \\ \\ \frac{1}{x} = \frac{1}{3} \\ \\ x = 3$