Look at the question, you know right away that m=-2/3 and b=-3. To do part a, plug 3 into x. That will be y= -2/3(3)-3. By order of operations, -2-3 which is -5. For part b, plug 0 into y. That will be 0= -2/3x-3. Add three to both sides (3= -2/3x). Then divide both sides by -2/3 (-4.5=x). The answer for b is -4.5.