For question 5, you need to solve region A and B separately as definite integrals. Then write them in a fraction to show the ratio of there areas. If you need any more help just let me know.
As for question 6... To find Q, sub in y=0 into the straight line equation. To find P, solve both equations simultaneously. For part b, draw a vertical line through the P and the x axis so the area is divided in two. Solve the two areas individually and then add them together to get the answer.
