Question

a/b=c/d=k , 3a-4c/36-12d=k/3, b=? ​

Answer 1

$frac{a}{b} = frac{c}{d} = k \ frac{3a - 4c}{36 - 12d} = frac{k}{3} \ frac{3a - 4c}{3(12 -4 d)} = frac{k}{3} \ frac{3a - 4c}{12 - 4d} = k \ frac{3a - 4c}{12 - 4d} = frac{c}{d} \ 3ad - 4cd = 12c - 4cd \ ad = 4c \ ad = cb \ = > cb = 4c \ b = 4.$