Question

$\frac{5x + 5}{25} = \frac{21}{15}$

Answer 1

$\frac{5x + 5}{25} = \frac{21}{15} \\ \\ (5x + 5) \times 15 = 25 \times 21 \\ \\ (5x \times 15) + (5 \times 15) = 25 \times 21 \\ \\ 75x + 75 = 525 \\ \\ 75x = 525 - 75 \\ \\ 75x = 450 \\ \\ x = 450 \div 75 \\ \\ x = 6$