Question

C. Directions: Solve for the indicated variable in each problem and show your complete solutions.
.
12-13. If a varies directly as b, and a=7 when b=5, find a when b=-3.
14-15. If a varies inversely as b, and a=12 when b=4, find a when b=-16.

Answer 1

Answer:

$1.) \: \frac{a}{b} = \frac{7}{5} \\ \frac{a}{ - 3} = \frac{7}{5} \\ a = \frac{7 \times ( - 3)}{5} \\ a = - \frac{21}{5} = - 4.2$

$2.) \: \: a \times b = 12 \times 4 \\ a \times 16 = 12 \times 4 \\ a = 12 \times \frac{4}{16} \\ a = 3$