5. (20 points) Evaluate the indefinite integral by substitution: at bx2 (1) dx (2) sec' xtanxdx V3ax + bx3 6. (30 points) Evaluate the definite integral by substitution: 21 3 (1) V1+ 13xdx (2) dx xVx - 2dx Jo V( 1 + 3x) 2 (3 ) 2 7. (30 points) Sketch the region enclosed by the given curves. Decide whether to integrate with respect to x or y. (1) y = x, y= 2- x (2) y = 1/x , y = 8x, y= x/8