Step-by-step explanation:
This is the photo of the construction you needed
Answer: (a) x + 2y = -1 and 3x + y = 1
<u>Step-by-step explanation:</u>
I am not sure what the purpose was for the colored lines but I included them on the graph (below).
$122.57 • 4 + $555.28 = $1,045.56
$136.71 • 4 + $585.34 = $1,132.18
$1,132.18 - $1,045.56 = $86.62
"Isolate the constant by adding 7 to both sides of the equation."
This step separates the non-squareable 7 and the squareable

.
"Add 9 to both sides of

to form a perfect square trinomial while keeping the equation balanced."
After separating the non-squareable, add the number which makes the first or left side a perfect square trinomial. The formula to find the number is:

.
When we plug the values:
Simplify:

"Write the trinomial

as

squared."
When you factor

, you will get

.
"Use the square root property of equality to get

."
The 16 is coming from the part when we add 9. We needed 9 on the left side for a perfect square, but to protect the balance of the equality, we need to add 9 to the right side too. When we add 7 and 9, we got 16, and that is where it came from.
"Isolate the variable x to get solutions of -1 and 7."
To isolate x we branched the plus-minus sign: