## College Algebra (6th Edition)

$x = 0.20$
$\log (x+7) - \log 3 = \log (7x+1)$ $\log \frac{x+7}{3} = \log (7x+1)$ $\log \frac{x+7}{3} - \log (7x+1) = 0$ $\log \frac{x+7}{3(7x+1)} = 0$ $\log \frac{x+7}{21x+3} = 0$ $1 = \frac{x+7}{21x+3}$ $\frac{x+7}{21x+3} = 1$ $x+7 = 1(21x + 3)$ $x+ 7 = 21x + 3$ $x - 21x = - 7 + 3$ $-20x = -4$ $x = \frac{4}{20}$ $x = \frac{1}{5}$ by GDC / calculator $x = 0.20$