with solution in testB. PLS HELP GRADE 10

Answer:
activity 1
1. C
2. D
3. B
4. D
5. D
B.
6. 2(4) + y = 12
8 + y = 12
Y=12 - 8
Y= 4
7. (-3)² -2(-3) - 15 =0
9 + 6 - 15 = 0
15 - 15 = 0
0 = 0
X = -3
8. x²-100 = 0
(10)²-100=0
100 - 100 = 0
0 = 0
X = 10
9. x+1 ÷ x³-x²-17x -15
I don't know The Answer on this one
goodluck with it