Answer:
7. 2x-10=x+30
2x-x=30+10
x=40
8. c
9.3x-20=2(x+5)
3x-20=2x+10
3x-2x=10+20
x=30
answer: B
10. 5x-6=3x-1
5x-3x=-1+6
2x=5
x=2.5
substitute
(5x-6)+(3x-1)=5(2.5)-6 + 3(2.5-1)
=(12.5-6)+(7.5-1)
=6.5+6.5
=13
answer: C
11. B.
12. C
