Answer:
x = 1 or x = -5
Step-by-step explanation:
We are given;
- The quadratic equation, x² + 4x - 13 = -8
We are required to solve the equation using the completing square method.
To do this, we use the following steps;
Step 1: We make sure the coefficient of x² is one
x² + 4x - 13 = -8
Step 2: Combine the like terms (take the constant term to the other side)
x² + 4x - 13 = -8
x² + 4x = -8 + 13
we get
x² + 4x = 5
Step 3: We add the square of half the coefficient of x on both sides of the equation
Coefficient of x = 4
Half of coefficient of x = 2
Square of half the coefficient of x = 2² (4)
We get;
x² + 4x + (2²) = 5 + (2²)
Step 4: Put x and 2 under one square and the solve the other side of the equation.
We get
(x + 2)² = 5 + 4
(x + 2)² = 9
Step 5: Get the square root on both sides of the equation;
(x + 2)² = 9
√(x + 2)² = ±√9
(x + 2)= ±3
Therefore;
x+2 = + 3 or x + 2 = -3
Thus, x = 1 or -5
The solution of the equation is x = 1 or x = -5
Answer:


Step-by-step explanation:
Given



Required
Find P(A) and P(B)
We have that:
--- (1)
and
--- (2)
The equations become:
--- (1)

Collect like terms


Make P(A) the subject

--- (2)


Substitute: 
![[0.770 - P(B)] * P(B) = 0.144](https://tex.z-dn.net/?f=%5B0.770%20-%20P%28B%29%5D%20%2A%20P%28B%29%20%3D%200.144)
Open bracket

Represent P(B) with x

Rewrite as:

Expand

Factorize:
![x[x - 0.45] - 0.32[x - 0.45]= 0](https://tex.z-dn.net/?f=x%5Bx%20-%200.45%5D%20-%200.32%5Bx%20-%200.45%5D%3D%200)
Factor out x - 0.45
![[x - 0.32][x - 0.45]= 0](https://tex.z-dn.net/?f=%5Bx%20-%200.32%5D%5Bx%20-%200.45%5D%3D%200)
Split

Solve for x

Recall that:

So, we have:

Recall that:

So, we have:


Since:

Then:


The standard deviation of the sample proportion is:

The z-score for 0.7 is:

Reference to a standard normal distribution table shows that the probability that at least 70% of the sample prefers coke to pepsi is 0.8944 or 89.44%.
The answers to the questions