SOLUTION: Solve the question by the method of elimination by substitution :- Question :- 3x-4y=20 x+2y=5

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Question 370032: Solve the question by the method of elimination by substitution :-
Question :-
3x-4y=20
x+2y=5
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Substitution or elimination?
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Substitution:
1.3x-4y=20
2.x%2B2y=5
From eq. 2,
x=5-2y
Substitute into eq. 1,
3%285-2y%29-4y=20
15-6y-4y=20
-10y=5
highlight%28y=-1%2F2%29
Then from eq. 2,
x=5-2%28-1%2F2%29
x=5%2B1
highlight%28x=6%29
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Elimination:
1.3x-4y=20
2.x%2B2y=5
Multiply eq. 2 by (2) and add to eq. 1,
3x-4y%2B2x%2B4y=20%2B10
5x=30
highlight_green%28x=6%29
Then use either equation to solve for y.
18-4y=20
-4y=2
highlight_green%28y=-1%2F2%29