Question

Five over seven plus blank over six equals fifty one over forty two

Answer 1

Answer:

The blank is 3

Step-by-step explanation:

1 - Give the blank a variable

x = our blank

2 - Write it out

$\frac{5}{7} + \frac{x}{6} = \frac{51}{42}$

3 - Get the denominators equal

$\frac{5}{7}(\frac{6}{6}) +\frac{x}{6}(\frac{7}{7}) = \frac{51}{42} \\\frac{30}{42}+\frac{7x}{42} = \frac{51}{42}$

4 - Simplify

$\frac{30+7x}{42} = \frac{51}{42} \\ \frac{30+7x}{42} = \frac{51}{42}$

5 - Solve for the numerators

30+7x = 51

-30         -30

      7x = 21

        x = 3