Question

Calculați ab-1,stiind ca a supra 3=7 supra b b)Calculati 3ab+5,stiind ca 3a supra 5=1supra b

Answer 1

$\frac{a}{3} = \frac{7}{b} \\ ab = 21 \\ ab - 1 = 21 - 1 = 20 \\ \\ \\ \frac{3a}{5} = \frac{1}{b} \\ 3ab = 5 \\ 3ab + 5 = 5 + 5 = 10$