Intermediate Algebra (12th Edition)

We simplify our line equation: $y-1\gt 3$ $y\gt 3+1$ $y\gt 4$ This is a horizontal line ($y=constant$) going through $y=4$. We know that if an inequality has an "equal" sign (e.g. "$\leq$" or "$\geq$"), then a solid line should be graphed. If the inequality does not have an "equal" sign (e.g. "$\lt$" or "$\gt$"), then a dashed line should be graphed. We also know that if an inequality has a "less than" sign (e.g. "$y\lt$..." or "$y\leq$..." or "$x\lt$..." or "$x\leq$..."), then the shading should be below the line (or left for vertical lines). If the inequality has a "greater than" sign (e.g. "$y\gt$..." or "$y\geq$..." or "$x\gt$..." or "$x\geq$..."), then the shading should be above the line (or right for vertical lines). In our case, we must graph a dashed line and shade above. See the resulting graph.