Rearrange, Then Shade

When y is not alone on the left, solve for y first, the same way you rearrange an equation. The only extra rule is the flip rule for inequalities. To rearrange $2x+y \le 3$, subtract 2x from both sides to get $y \le -2x+3$. There is no flip, because you did not multiply or divide by a negative. Now you can read the graph from it. The boundary line is $y = -2x+3$, it is solid, and the shading is below it.

The sign flips only when you multiply or divide both sides by a negative number. For example, dividing $-y < x-2$ by -1 gives $y > -x+2$. Every rule for rearranging an inequality on the number line also holds for an inequality in x and y.