Algebra 1

$(0,0)$ and $(1,-9)$
Let us find the slope of the line that passes through $(0,0)$ and $(1,-9)$ to prove that it is $-9$: To find the slope, we use the formula $m=\frac{y_2-y_1}{x_2-x_1}$. We plug in the $x$ and $y$ values: $m=\frac{-9-0}{1-0}$ We simplify above and below the fraction bar with subtraction: $m=\frac{-9}{1}$ Then, we divide the fraction: $m=-9$ Therefore, these two points lie on a line with slope $m=-9$.