Question

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Which of the systems of equations has a solution of (-2,6)? A.
y= 2x + 10
y = 3x - 6
В.
y - 2x = 2
y + 2x = 10 C. x - y = 9
y = x + 9
D. x + 2y = 10
-4x - y = 2

Answer 1

D

Explanation:

X+2y=10

-4x-y=2

first, isolate x in first equation: x=10-2y

substitute value of x in first equation (10-2y) into second equation:

-4(10-2y)-y=2

-40+8y-y=2

7y=42

y=6

put value of y (6) into either equation to solve for x

x+2(6}=10

x+12=10

x=-2

x=-2, y=6

prove by inserting x and y values into either equation

-4x-y=2

-4(-2)-6=2

8-6=2

2=2

or

x+2y=10

-2+2(6)=10

-2+12=10

10=10