15. -(-7y + 12) = 7y - 12
16. 1/a = 16/18
cross multiply
16a = 18
a = 18/16 = 9/8
17. 8x - 12 = 4x + 24
8x - 4x = 24 + 12
4x = 36
x = 36/4
x = 9
18. -6b > 42 4b > -4
b < 42/-6 b > -4/4
b < - 7 b > -1
so b < -7 and b > -1
19. 6 more then the product of 8 and n
6 + 8n
20. 45 = 3b + 69
45 - 69 = 3b
-24 = 3b
-24/3 = b
-8 = b
I think you doubled them
ratio of dogs to cats=3:2
30 animals total
3+2=5 units
30=5unit
divide by 5
6=1unit
dogs=3 unit
6=1unit
times 3
18=3unit=dogs
18 dogs
(7 times 200)plus (7 times 50) plus (7 times 6)
The baker uses 336 ounces in 2 weeks.
Or, if that hyphen between the lower index and 3 is actually a negative sign, then the sum is -189.
