Chapter 4 - Exponential and Logarithmic Functions - Exercise Set 4.4 - Page 490: 77

$x = \frac{4}{3}$ $x = 1.33$

$\log (x+4) = \log x + \log 4$ $\log (x+4) = \log (x)(4)$ $\log (x+4) = \log 4x$ $\log (x+4) - \log 4x = 0$ $\log \frac{x+4}{4x} = 0$ $1 = \frac{x+4}{4x}$ $\frac{x+4}{4x} = 1$ $x+4 = 1(4x)$ $x+4 = 4x$ $x + 4 - 4x = 0$ $-3x + 4 = 0$ $-3x = - 4$ $x = \frac{4}{3}$ by GDC / calculator $x = 1.33$