Chapter 5 - Exponential Functions - 5.2 Solving Equations Using Exponent Rules - 5.2 Exercises - Page 438: 78

$m \approx 1.9$

$4m^{7} + 20 = 380$ $4m^{7} = 380 - 20$ $4m^{7} = 360$ $m^{7} = 90$ $m = 90^{\frac{1}{7}}$ $m = 1.901...$ $m \approx 1.9$ Check: $4m^{7} + 20 \overset{?}{=} 380$ $4(1.9...)^{7} + 20 \overset{?}{=} 380$ $4(89.99...) + 20 \overset{?}{=} 380$ $(359.99....) + 20 \overset{?}{=} 380$ $379.99... \overset{?}{=} 380$ $379.99... \approx 380$