Answer:
- The two solutions are:

- The next and every step are below.
Explanation:
1.
: Given (addition property / add - 3 to both sides)
2.
: Given (commom factor - 2)
3. 
To obtain the perfect square it was added the square of half of the coefficient of x: (1/2)² = 1/4, inside the parenthesis.
Since, the terms inside the parentthesis are multiplied by - 2, you have to add - 2 (1/4) = - 1/2 to the left side of the equation.
4. Now, you have that the trinomial x² - x + 1/4 is a square perfect trinomial which is factored as (x - 1/2)² and get the expression:

5. Divide both sides by - 2 to get the next expression:

6. The last step is to extract squere root from both sides of the equality:

Answer:
6x 6x
I might be wrong
Step-by-step explanation:
I hope that's the answer
So firstly, add both sides by 6: 
Next, multiply both sides by 4, and your answer will be 
Answer:
x = 15
Step-by-step explanation:
Let the x represents altitude.
Therefore, by geometric mean property:

Answer:
x = 8
Step-by-step explanation:
The mean is the average of the population.
Multiplying the mean by 8 terms will get you the total sum.
12 * 8 = 96
Subtracting all the values from the total sum should get you x.
96 - 18 - 15 - 18 - 3 - 3 - 19 - 12 = 8