Apparently the last two answers I have for pet B are incorrect. Please help me see where I went wrong. Ty!!

EXAMPLE 4 Evaluate the following integrals by interpreting each in terms of areas. (a) 9 - x2 dx ( b ) ( x - 3) dx SOLUTION (a) Since f(x) = \\ 9 - x2 2 0, we can interpret this integral as the area under the curve y = V9 - x2 from 0 to 3 . But since y2 = 9 - 2 we get x2 + y2 = 9, which shows th the graph of f is a quarter-circle with radius 3 in the top figure. Therefore, 9TC V 9 - x2 dx = _ x(3)2 = 4 (b) The graph of y = x - 3 is the line with slope 1 shown in the bottom figure. We compute the integral as the difference of the areas of the two triangles: (x - 3) dx = A1 - A2 = 24.5 - 4.5 = 20