Solution: The correct option is d. 8.75
<u>Explanation:</u>
The formula for variance is:
First we need to find the mean 
of the given data:
Now let's find 
, please have a look at the attached picture:
Answer:
7. ∠CBD = 100°
8. ∠CBD = ∠BCE = 100°; ∠CED = ∠BDE = 80°
Step-by-step explanation:
7. We presume the angles at A are congruent, so that each is 180°/9 = 20°.
Then the congruent base angles of isosceles triangle ABC will be ...
∠B = ∠C = (180° -20°)/2 = 80°
The angle of interest, ∠CBD is the supplement of ∠ABC, so is ...
∠CBD = 180° -80°
∠CBD = 100°
__
8. In the isosceles trapezoid, base angles are congruent, and angles on the same end are supplementary:
∠CBD = ∠BCE = 100°
∠CED = ∠BDE = 80°
Step-by-step explanation:
x⁴ − 5x³ + 11x² − 25x + 30
x⁴ − 5x³ + 6x² + 5x² − 25x + 30
x² (x² − 5x + 6) + 5 (x² − 5x + 6)
(x² + 5) (x² − 5x + 6)
(x² + 5) (x − 2) (x −3)
The zeros are 2, 3, and ±√5i.
