Answer for question 2:
x= -5
Step-by-step explanation:
0= 6x +30
-6x= 30
x= 30/-6
x= -5

Step-by-step explanation:
This can be written as;

Perform factorization
9-a²=difference of squares formula
(3+a)(3-a)
4a²-4a-24
4(a²-a-6)
4(a²-3a+2a-6)
4(a(a-3)+2(a-3))
4((a+2)(a-3))
a²-6a+9
a²-3a-3a+9
a(a-3)-3(a-3)
(a-3)(a-3)
Rewrite the operation as;

cancel common to remain with;

Learn More
Factorization : brainly.com/question/11930808
Keywords : Operation
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Part 1.
A is.
45 and 34 wood pieces left
B is.
It takes 11 cause 100-89=11 and 11+89=100 and it keeps subtracting 11.
C is.
I dont understand the question(sorry)
D is.
At least 9 shelves,
100-11=89
89-11=78
78-11=67
67-11=56
56-11=45
45-11=34
34-11=23
23-11=12
12-11=1
And you would have 1 wood piece remaining!!