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Answer: Choice B
(-2, 5)
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Explanation:
The original system is
Multiply both sides of the second equation by 3. Doing so leads to this updated system of equations
Now add straight down
The x terms add to -4x+3x = -1x = -x
The y terms add to 3y+(-3y) = 0y = 0
The terms on the right hand sides add to 23+(-21) = 2
We end up with the equation -x = 2 which solves to x = -2
Now use this to find y. You can pick any equation with x,y in it
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-4x+3y = 23
-4(-2)+3y = 23
8+3y = 23
3y = 23-8
3y = 15
y = 15/3
y = 5
Or
x-y = -7
-2-y = -7
-y = -7+2
y = -5
y = 5
Either way, we get the same y value.
So that's why the solution is (x,y) = (-2, 5)
Overall dimensions of the page in order to maximize the printing area is page should be 11 inches wide and 10 inches long .
<u>Step-by-step explanation:</u>
We have , A page should have perimeter of 42 inches. The printing area within the page would be determined by top and bottom margins of 1 inch from each side, and the left and right margins of 1.5 inches from each side. let's assume width of the page be x inches and its length be y inches So,
Perimeter = 42 inches
⇒
width of printed area = x-3 & length of printed area = y-2:
area =
Let's find :
=
, for area to be maximum
= 0
⇒
And ,
∴ Overall dimensions of the page in order to maximize the printing area is page should be 11 inches wide and 10 inches long .