Please help on that excercise

Step-by-step explanation:

16. d-4 = -7

or, d = -7+4

or, d = -3

therefore, d = -3.

17. c-34 = 20

or, c = 20+34

or, c = 54

therefore, c = 54

18. a-4 = -18

or, a = -18 + 4

or, a = -14

therefore, a = -14

19. r-3 = 8

or, r = 8+3

or, r = 11

therefore, r = 11

20. z-100 = 100

or, z = 100+100

or, z = 200

therefore, z = 100

21. 5 = d - 1

or, 5+1 = d

or, 6 = d

or, d = 6

therefore, d = 6

8(-10x+3.5y-7)

8×-10x + 8×3.5y + 8×-7

-80x + 28y - 56

therefore

-80x+28y-56 is the correct answer