Answer: Choice B) (24,10)
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Work Shown:
2x - 4y = 8
2( x ) - 4y = 8
2( 3y-6 ) - 4y = 8 ... notice x has been replaced with 3y-6
2(3y)+2(-6) - 4y = 8
6y-12 - 4y = 8
2y-12 = 8
2y-12+12 = 8+12 ... add 12 to both sides
2y = 20
2y/2 = 20/2 ... divide both sides by 2
y = 10
If y = 10, then
x = 3y-6
x = 3*10-6 ... replace y with 10
x = 30-6
x = 24
Put together, the solution is (x,y) = (24,10)
which is why the answer is choice B
As a check, we can plug (x,y) = (24,10) into each equation
x = 3y-6
24 = 3*10 - 6
24 = 30 - 6
24 = 24 ... true equation
and similarly for the second equation as well
2x-4y = 8
2*24 - 4*10 = 8
48 - 40 = 8
8 = 8 ... true equation
Both equations are true when (x,y) = (24,10) so the solution is confirmed