Answer: 7
Step-by-step explanation:
To solve this problem you must apply the proccedure shown below:
1. You know that a multiplication has the following form:
a*b=c
Where a and b are the factors and c is the product.
2. You know one of the factor, then you can find the second one as following:
12*b=84
b=84/12
b=7
Therefore the answer is 7.
The answer to 2 is 14 and the answer to 4 is b
For 10 here is the answer and for 9 i’ll reply to my comment
What do you need to find I need to know that so I can solve it