In problems 1-12, calculate the definite integral, given that Sixdx = 7.5 ff x2 dx = 21 x2 dx = 61 1. [*(-x - 5x2)dx 2. , dx 3. S;(-7x - 9x2) dx 4. S= (7x - 7x2 ) dx 5. = (5x2 - 8x)dx 6. S(x2 - 11x) dx 7. [ ( x2 - 2x)dx 8. 15 -dx 9. S (x - ) dx 10. (-8x + =x2) dx 11. (-10x2 + x)dx 12. JA x(5 - 7x)dx