Let’s use y as a replacement for a number. You would do 3y-7 since you multiply by three and take away seven.
21\25
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Answer:

Step-by-step explanation:
The midpoint of two points is the average of the x coordinates and the average of the y coordinates.
Given
A(3, -1)
and we let the other end point B be B(x,y)
and midpoint is (-7,10)
So, the average of 3 and x is -7, and
the average of -1 and y is 10
We can solve for x first:

and now solving for y:

So, the other point B is:

Answer: Y=(
) x-7
Step-by-step explanation: