Chapter F - Foundations: A Prelude to Functions - Section F.2 Graphs of Equations in Two Variables; Intercepts; Symmetry - F.2 Assess Your Understanding - Page 18: 74

$b=2$

If a point is on the graph, the $(x,y)$ coordinates satisfy the equation. Here, $(-2,b)$ is on th graph, therefore we should plug in these coordinates into the given equation to obtain: $2x+3y=2$ $2(-2)+3(b)=2$ $-4+3b=2$ $3b=6$ $b=2$ The point $(-2,2)$ is on the graph and $b=2$