Sum of Interior Angles of any poligon, where n is the number of sides: =
(n-2) × 180°
---------------------
(7 - 2) * 180° =
5 * 180 =
900°
[d]
Answer:

Step-by-step explanation:
(11)²=(6)²+ (y)²
121=36 +(y)²
y² =121 –36
y²=85

16 n^2 -10n + 129 = 8n^2 -8
We collect the terms:
8n^2 -10n + 137 = 0
The steps for completing the square:
1) Move the "non X" (or "non N") term to the right:
8n^2 -10n = -137
<span>2)<span> Divide the equation by the coefficient of N² which in this case is 8
n^2 -1.2n = </span></span><span><span>-17.125
</span>
3) Take the coefficient of "N"; divide it by 2; square it; add it to both sides of the equation.
-1.2 / 2 = -.6
-.6^2 = .36
</span>
n^2 -1.2n +.36 = <span>-17.125
+.36
Take the square root of both sides:</span>
(n-.6)*(n-.6) = sq root(
<span>
<span>
<span>
-16.765
</span>
</span>
</span>
)
That's about as far as I can go.
Answer:
n = 18
Step-by-step explanation:
2n - 5 = 31
Add 5 to each side
2n - 5+5 = 31+5
2n = 36
Divide each side by 2
2n/2 = 36/2
n = 18
Hmm it would be k(x)=2(5x) or it could be k(x)=10x
Hope this helps!