Can anybody tell me if these problems are correct? Please look if you are good at math are jus know it.?

Question

2. 5y-x for y= 8 and y= -11 my answer 29

4. 5s-3t for s= -14 and t =13 my answer 15

6.8x+4y-2z for x = 5, y = 17, and z= -8 didn't come up with one. plz tell me.

8.-x for x = -8 my answer -8

10. -(m) for m = 12 my answer 12

12. -(y +20) for y = -6 my answer -14

14.-(y+2) for y = 1 my answer 2

16. IpI + IqI for p = 21 and q = -12 my answer -12

18. Ip+qI for p= 21 and q = -9 my answer 30

20. Ip-qI for p= 31 and q = -6 my answer 25

Answer 1

2,     51    typo by you

4 .      -109

6 .   124

8.     8

10.     -12

12.   -14

14 .     -3

16.    33

18 .      12

20.        37

Answer 2

xanadu is 100% correct

Answer 3

8. the answer is 8