# How do you graph -3y<21 on the coordinate plane?

Oct 29, 2017

See a solution process below:

#### Explanation:

Divide each side of the inequality by $\textcolor{b l u e}{- 3}$ to solve for $y$ while keeping the inequality balanced. However, because we are multiplying or dividing an inequality by a negative number we must reverse the inequality operator:

$\frac{- 3 y}{\textcolor{b l u e}{- 3}} \textcolor{red}{>} \frac{21}{\textcolor{b l u e}{- 3}}$

$\frac{\textcolor{b l u e}{\cancel{\textcolor{b l a c k}{- 3}}} y}{\cancel{\textcolor{b l u e}{- 3}}} \textcolor{red}{>} - 7$

$y > - 7$

To graph this we will draw a horizontal at $- 7$ on the vertical axis.

The line will be a dashed line because the inequality operator does not contain an "or equal to" clause.

We will shade above the the line because the inequality operator does contain a "greater than" clause:

graph{y>=-7 [-15, 15, -12.5, 12.50]}