I'm more visual, but if you're not, and this confuses you, ask me, and I'll explain it.
Answer:
CD = 16.5
Step-by-step explanation:
To find the distance between two points, use this formula: 
point C can be info set 1: (10, -1) x₁ = 10 y₁ = -1
point D can be info set 2: (-6, 3) x₂ = -6 y₂ = 3
Substitute the information into the formula

Simplify inside each bracket
Square the numbers
Add inside the root
Enter into calculator
Rounded to the nearest tenth, the first decimal
The distance CD is 16.5.
Answer: x^2 - 14x + 49
Explanation:
1) Divide the coefficient of x by 2:
14 / 2 = 7
2) so you have to add 7^2 = 49
x^2 - 14x + 49
3) that trinomial is equivalent to:
=> (x - 7)^2
4) prove that using the formula (a - b)^2 = a^2 - 2ab + b^2
(x - 7)^2 = x^2 - 14x + 49
Then you have to add 49 to complete the square. and form a perfect square trinomial.
5(24+4) Also 20(6+1)...................