Answer:
x = 15
Step-by-step explanation:
Given
See attachment
Required
Find x
The figure in the attachment is a quadrilateral and the angles in a quadrilateral add up to 360.
So, we have:
90 + 6x + 5+ 10x - 40 + 4x + 5 = 360
Collect like terms
6x + 10x + 4x = 360 - 90 - 5 + 40 - 5
20x = 300
Divide both sides by 20
x = 15
Hence, the value of x is 15
Summaation of a sequence
or see a smaller scale
from 1 to 10
notice
1+10=11
2+9=11
etc
5+6=11
10/2=5
there are 5 pairs
5*11=55
so
1 to 100
1+100=101
2+99=101
...
50+51=101
100/2=50
there ar 50 pairs
50 times 101=5050
the sum is 5050
If i'm correct, the answer should be
-3a
hope this helped! 8)