Completing the square follows the principle of taking

and converting it into

where d is the 'correctional number' as I like to call it - i.e. the number that converts the expanded bracket into the +c, since the expanded bracket will give us

.
In this case, 2/2=1 so we have the first part:

.
Expanding this gives us

. We need c to be 9, so we can just add 8.
Putting this together:

Now we can solve it more easily.
Rearranging:
X+10=15
Isolate x by subtracting 10 from both sides
x+10-10=15-10
x=5
Final answer: B
Check by plugging the value in
5+10=15
True
Your answer would be X=8 and Y=11.
Answer:
x = -2
y = -5
Step-by-step explanation:
We can solve this algebraically (substitution or elimination) or graphically. I will be using elimination:
Step 1: Add the 2 equations together
-8y = 40
y = -5
Step 2: Plug <em>y </em>into an original equation to find <em>x</em>
-3(-5) + 10x = -5
15 + 10x = -5
10x = -20
x = -2
And we have our final answers!