Step-by-step explanation:
$7 = 1 package socks
%56 = ??
$56/$7 × 1 package socks
= 8 × 1
= 8 package socks
Hope it helps!

There are 2 roots so the only way to complete the square is,
![y=2x^2+8x-9\\y=2[(x^2+4x)]-9\\y=2[(x^2+4x+4)-4]-9\\y=2[(x+2)^2-4]-9\\y=2(x+2)^2-8-9\\y=2(x+2)^2-17](https://tex.z-dn.net/?f=y%3D2x%5E2%2B8x-9%5C%5Cy%3D2%5B%28x%5E2%2B4x%29%5D-9%5C%5Cy%3D2%5B%28x%5E2%2B4x%2B4%29-4%5D-9%5C%5Cy%3D2%5B%28x%2B2%29%5E2-4%5D-9%5C%5Cy%3D2%28x%2B2%29%5E2-8-9%5C%5Cy%3D2%28x%2B2%29%5E2-17)
Just factor 2 out of 2x^2+8x (just ignore the -9) then find the number that will make the terms be able to complete the square.
then complete the square and multiply 2 inside the brackets.
subtraction as you already get the vertex form and know how to complete the square.
Vertex Form: 
You can use Substitution to solve this problem:
4x-y=20
-y=-4x+20
y=4x-20
Now you have two equations, and you use the first one to substitute into the second one.
y=4x-20 and -2x-2y=10
-2x-2(4x-20)=10
-2x-8x+40=10
-10x+40=10
-10x=-30
-x=-3
x=3
Now that we have figured out what x is, we can substitute x in to one of the equations to figure out y.
4x-y=20 x=3
4(3)-y=20
12-y=20
-y=8
y=-8
<em><u>So your answer would be x=3 and y=-8</u></em>
<u>Question 6</u>
1)
,
, O is the midpoint of
,
(given)
2)
are right angles (perpendicular lines form right angles)
3)
are right triangles (a triangle with a right angle is a right triangle)
4)
(a midpoint splits a segment into two congruent parts)
5)
(LL)
<u>Question 7</u>
1)
are right angles), 
2)
(reflexive property)
3)
are right triangles (a triangle with a right angle is a right triangle)
4)
(LL)
5)
(CPCTC)
<u>Question 8</u>
1)
, point D bisects
(given)
2)
are right angles (perpendicular lines form right angles)
3)
are right triangles (a triangle with a right angle is a right triangle)
4)
(definition of a bisector)
5)
(reflexive property)
6)
(LL)
7)
(CPCTC)