Chapter 1, Equations and Graphs - Section 1.9 - Solving Equations and Inequalities Graphically - 1.9 Exercises - Page 158: 5

Solving algebraically and graphically, we get the solution $x=-4$.

Solve algebraically: $x-4=5x+12$ (Substract with $5x$) $-4x-4=12$ (Add with $4$) $-4x=16$ $x=\frac{16}{-4}$ $x=-4$ Solve graphically: We sketch two graphs of $y_1=x-4$ and $y_2=5x+12$ on the same plane as shown below. We can see that both intersect at $x=-4$. Then, the solution of the equation is $x=-4$.