Answer
$x \approx 33.333$
Work Step by Step
$\log (3x) - 30 = -28$
$\log 3x = -28 + 30$
$\log 3x = 2$
$10^{2} = 3x$
$100 = 3x$
$x = \frac{100}{3}$
$x \approx 33.333$
Check:
$\log (3(\frac{100}{3})) - 30 \overset{?}{=} -28$
$\log (100) - 30 \overset{?}{=} -28$
$\log_{10} (10^{2}) - 30 \overset{?}{=} -28$
$2\log_{10} (10) - 30 \overset{?}{=} -28$
$2(1) - 30 \overset{?}{=} -28$
$2 - 30 \overset{?}{=} -28$
$-28= -28$
