If my calculations are correct I think it's 50
Ivan only, because an odd number of negatives does not always make negatives while an even number does.
First you cancel 7 and 28, and 3 and 9, so that leaves you with 4/3 x 15/17, then you cancel 3 and 15 so you get 4x5/17 which should give you 20/17!
Answer:
z = 0
Step-by-step explanation:
3 (z + 7) = 21
3z + 21 = 21
3z = 0
z = 0