ecMathGeek gave a short explanation for this question, look at it
They gave the solutions as -3.3 or 0.3 so i looked at the graph for those x-values to see if any graphs intersected at that those points. i found that the quadratic and the line y = -x - 2 intersected there, so i just equated them (since intersecting points occur when one graph equals the other) and simplified the answer to look like a quadratic. when i used the quadratic formula, i was just verifying my answer, you would not have to do that.......do you understand now, or is something still unclear?
I can't work out how you got the second onethough.