Question

X upon 3 + 1 equal to 7 upon 15

Answer 1

x / 3+1 = 7/15
x = 4*7/15
x = 28/15
x = 1.8

Answer 2

$\frac{x}{3} + 1 = \frac{7}{15} \\ \frac{x + 3}{3} = \frac{7}{15} \\ x + 3 = \frac{7}{15} \times 3 \\ x + 3 = \frac{7}{5} \\ x = \frac{7}{5} + 3 \\ x = \frac{7 + 15}{5} \\ x = \frac{22}{5} = 4.4$
Hope it help you.
:-)