Answer:
a
Step-by-step explanation:
1. x=10,-10
2. x = 5
x = -5
3. x=-5
4. x ∈ {4,- 3/2}
see picture attached.
i hope this helped !!
245
let 'c' = total coins
2/7 = 70/c
2c = 490
c = 245
