Answer:
18
Step-by-step explanation:
(3 x -3) equals -9, -9 x -2 equals 18 since the negatives cancel each other out.
In this question, they gave you the system of equations. You just need to use the two of them.
We want to find the m or the number of the multiple-choice questions. So we need to turn our last equation in the form of 'm's by translating the 'f's into 'm's.


If we know the m form of f, we can convert the second equation and find the answer:

Plug in the m value of f:

Distribute the 5:

Subtract -75 from both sides:

Combine like terms:

Divide both sides by -2:

So, we learned that the number of the multiple-choice questions is 12.
Answer:
- 1
Step-by-step explanation:
Let the slope of one line be 's' , then according to the given condition that the slope of second line is negative reciprocal of the first , We obtain the slope of the second line as
.
So, the product of both the slopes is given by 
This shows that whatever the slopes may be if they are negative reciprocal of each other then their product will always be -1
Answer:
x=3
Step-by-step explanation:
I did a 2-column proof for the explanation :)