X = (12 +- sqrt (144 -4(7)(3))/14
x = (12 + - sqrt (144 - 84))/14
x = (12 + - sqrt(60))/14
x = (12 + - 2sqrt 15))/14
x = (6 + - sqrt 15) / 7
2/6 is the answer 1/2 1/2 0/2
The series 7 + 16 + 25 +34 +43 +52 + 61 is an illusration of arithmetic series
The sigma notation of the series is: 
<h3>How to write the series in sigma notation?</h3>
The series is given as:
7 + 16 + 25 +34 +43 +52 + 61
The above series is an arithmetic series, with the following parameters
- First term, a = 7
- Common difference, d = 9
- Number of terms, n = 7
Start by calculating the nth term using:
a(n) = a + (n - 1) * d
This gives
a(n) = 7 + (n - 1) * 9
Evaluate the product
a(n) = 7 - 9 + 9n
Evaluate the difference
a(n) = 9n - 2
So, the sigma notation is:

Read more about arithmetic series at:
brainly.com/question/6561461
Well, first you would have to draw the three pizzas, then spilt them all in half, so each friend would have a half of pizza! Hope this helped!
<span>m∠3 = 180 -(x + x - 6 )
= 180 - 2x + 6
= 186 - 2x</span>