x 2y z 15 5y 2z 16 z 3 a 22 b 16 c 157 d 8 Solve the s
Solution
2)
 2x + y - z = 3
 x - 3y + z = 7
 3x + 5y - 3z = 0
Add first two :
 3x - 2y = 10
Now, multiply the second by 3 :
 3x - 9y + 3z = 21
 3x + 5y - 3z = 0
Adding these to eliminate z :
 6x - 4y = 21
So, we have:
 3x - 2y = 10
 6x - 4y = 21
Multiply the first of these by 2 :
 6x - 4y = 20
 6x - 4y = 21
These cannot be simultaneously true
So, NO SOLUTION
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3)
 Well, this ones easy..
 Notice that the quadratic is graphed with solid lines
 So, it cannot be options A or B
And also, notice that we have shaded below the parabola
 So, it must be in the form
 y <=
So, option C
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5)
 (x-1)^2 + (y+2)^2 > 4
This is a circle of center = (1,-2)
 and radius = sqrt4 = 2
This is in either A or C
Now, we are shading everywhere outside it
So, option C

