Answer
a) $\frac{15}{x} = 4$
b) $12 - 3 = x$
c) $4x + 17= 21$
Work Step by Step
a) Since the quotient of 15 and the number $x$ is 4, we have,
$\frac{15}{x} = 4$.
b) Since three subtracted from 12 is the number $x$, we have
$12 - 3 = x$.
c) Since 17 added to four times the number $x$ is 21, we have,
$4x + 17= 21$.
