Answer:
No
Step-by-step explanation:
There can not be x and y both attached to one coefficient.
To determine the sum of the arithmetic series, simply remember that i is the pattern that you are going by which is 1,2,3.
The top value on the sigma sign tells you the final value that you must go to.
So use the equation to go from 1 to 18. So it would be 2(1) + 9 + 2(2) + 9 etc.
You know the angle sum of a square is 360 degrees.
So,
360=70+120+86+x
360=276+x
Then you solve for x by isolating it (minus 276 on both sides)
360-276=276-276+x
84=x
The last angle is 84 degrees.
Have a nice day:)
Answer:

Step-by-step explanation:
-
= 