Question

Afla nr a si bstiind ca sunt direct proportionale cu nr 2 si 7 si 2b-5a=28

Answer 1

$\frac{a}{2} = \frac{b}{7} \\ 2b - 5a = 28 \\ 7a = 2b \\ 7a - 5a = 28 \\ 3a = 28 \\ a = \frac{28}{3 } \\ b = \frac{7a}{2} = \frac{7 \times \frac{28}{3} }{3} = \frac{7 \times 28}{9} = \frac{196}{9}$