- Midpoint formula is
.
<h3>19.</h3>
So starting with this one, we will be solving for the coordinates of the unknown endpoint separately. Starting with the x-coordinate, since we know that the midpoint x-coordinate is 5 and the x-coordinate of N is 2, our equation is set up as such:
From here we can solve for the x-coordinate of Q.
Firstly, multiply both sides by 2: 
Next, subtract both sides by 2 and your x-coordinate is 
With finding the y-coordinate, it's a similar process as with the x-coordinate except that we are using the y-coordinates of the midpoint and endpoint N.

<u>Putting it together, the missing endpoint is (8,4).</u>
<em>(The process is pretty much the same with the other problems, so I'll go through them real quickly.)</em>
<h3>20.</h3>


<u>The missing endpoint is (7,2).</u>
<h3>21.</h3>


<u>The missing endpoint is (-5,1).</u>
It means that 15 times another number equals to your equation.
That's all I remember rn. Graphing site is desmos.com if you wanted to know.
Answer:
s=-4
Step-by-step explanation:
- combine like terms on each side and get 3s-12=6s
- subtract 3s from both sides to get -12=3s
- divide both sides by three and get s=-4
Rewrite and factor 9 and 21;
3•3+3•7= 3(3+7)
GCF for 9 and 21 is 3