Answer:

Step-by-step explanation:
Given:

Solve for:

Solution:
Step 1: Select the formula to solve for 
There are some ways to solve quadratic equations.
One of the simple way (if possible) is performing the factorization.
Another way is using the quadratic formula.
Here, we are going to use factorization.
Step 2: Perform factorization

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or 
Hope this helps!
:)
4.08, or 4 2/25 :) hope this helps
Answer:
A. <ECF and <BCF
Step-by-step explanation:
Complementary angles are angles that add up to give 90°
m<BCE = m<BCA = 90° (right angles)
m<ECF + m<BCF = m<BCA
m<ECF + m<BCF = 90° (Substitution)
Therefore, <ECF and <BCF are complementary angles.
Answer:
Step-by-step explanation:
Since; the density function diagrams were not included in the question; we will be unable to determine the best which depicts this problem.
However;
Let use X to represent the time required for the delivery.
Then X~N(3.8 ,0.8)
i.e
E(x) = 3.8
s.d(x) = 0.8
NOW; P(x>4) = P(X-3.8/0.8 > 4-3.8/0.8)
= P(Z > 0.25)
= 1-P(Z < 0.25)
=1 - Φ (0.25)
= 1 - 0.5987 ( from Normal table Φ (0.25) = 0.5987 )
= 0.4013
Thus; the probability a single delivery would take more than 4 hours is 0.4013
What is the z value corresponding to the interval boundary?
The z value is calculated as:


z = 0.25