solve the following equations by substitution method 5x+3y=21;2x-y=4
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Answered by
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5x + 3y = 21
2x - y = 4 multiplying 3 on both sides
6x - 3y = 12
now adding two equations
5x + 3y + 6x - 3y = 21 + 12
x = 3
y = 2x -4
y = 6- 4 = 2
2x - y = 4 multiplying 3 on both sides
6x - 3y = 12
now adding two equations
5x + 3y + 6x - 3y = 21 + 12
x = 3
y = 2x -4
y = 6- 4 = 2
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Answered by
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5x+3y=21
or,5x=21-3y
or,x=(21-3y)/5....................(1)
2x-y=4
putting the value of x as (21-3y)/5 from (1) we have,
(42-6y)/5-y=4
or,42-6y-5y=20
or,-11y=20-42=-22
or,y=-22/-11=2 .....................(2)
x=(21-3y)/5 ,
putting the value of y as 2 from (2) we have,
x=(21-6)/5=3
Ans:x=3
y=2
or,5x=21-3y
or,x=(21-3y)/5....................(1)
2x-y=4
putting the value of x as (21-3y)/5 from (1) we have,
(42-6y)/5-y=4
or,42-6y-5y=20
or,-11y=20-42=-22
or,y=-22/-11=2 .....................(2)
x=(21-3y)/5 ,
putting the value of y as 2 from (2) we have,
x=(21-6)/5=3
Ans:x=3
y=2
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