1. Dodo1

2. Luigi0210

$\int\limits_{7}^{8}f(x)=-8$ I think..

3. Luigi0210

|dw:1366155033606:dw|

4. Dodo1

5. Dodo1

how did you get this?

6. Luigi0210

Well I used the given information and graphed it out I graphed each integral individually

7. Luigi0210

And they gave the over value from 6-9 which is 6 So I added up both integral values: 14-x=6

8. Dodo1

I see. what about the second one?

9. Luigi0210

It would be the opposite.. since it's going backwards whenever the integral has a lower limit that is higher than the upper limit it'll be negative $\int\limits_{8}^{7}f(x)dx=-\int\limits_{7}^{8}f(x)dx$

10. Luigi0210

So it's -(-8)=8

11. Luigi0210

Does that make some sense? :l

12. Dodo1

the second one is wrong when I entred it

13. Luigi0210

Woops, I did not see that 6..

14. Luigi0210

$-\int\limits_{7}^{8} 6(-8)-6$ so it's 54 if I'm not mistaken again :/

15. Dodo1

correct! you are supre. could you explain?

16. Luigi0210

17. Dodo1

yes,

18. Luigi0210

Well since we know that: $\int\limits_{7}^{8}f(x)dx=8$ We can switch the integrals around and we already solved for $\int\limits_{7}^{8}f(x)dx$ we just plug in 8 for $-\int\limits_{7}^{8}6f(x)-6$

19. Luigi0210

so it'll be -[6(-8)-6] -[-48-6] -[-54] 54

20. Luigi0210

sorry i meant -8 on the first integral

21. Dodo1

thank you so much