## Intermediate Algebra for College Students (7th Edition)

$a.\qquad y=-3x$ $b.\qquad\left\{\begin{array}{ll} m=-3, & \text{slope}\\ b=0 & \text{y-intercept} \end{array}\right.$ $c. \qquad$Graph:
$(a)$ The slope-intercept form is $\ \ y=mx+b.$ ( m= slope, b= y-intercept) Solve for y: $\left[\begin{array}{l} 2x+y=0\\ y=-3x\\ \end{array}\right]$ $(b)$ $y=-3x+0\ \Rightarrow \ \left\{\begin{array}{ll} m=-3, & \text{slope}\\ b=0 & \text{y-intercept} \end{array}\right.$ $(c)$ Graphing, we have a starting point,$(0,0)$, since b=0. Now, the slope $m=\displaystyle \frac{\text{change in y}}{\text{change in x}}=-3=\frac{-3}{1}$, which we use like this: Increasing x by 1 (from x=0 to x=1), y decreases by $3$ units (from y=0 to y=$-3$). The line passes through $(1,-3).$ Two points define the line. Draw it.