Question

If 3/x+4y=7 and 5/x+6y=13, Find x and y by elimination method.

Answer 1

Step-by-step explanation:

3/x+4y=7

5/x+6y=13

3+4xy=7x --------(1)

5+6xy=13x...........(2)

multiplying eqn (1) ×5 and eqn (2) ×3 and subtracting the results

15+20xy=35x

15+18xy=39x

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×. +2xy= -4x

2xy=-4x

2y. = -4

• y. = -2

putting value of y in (1)

3+4xy=7x

3+4x×(-2)=7x

3=7x+8x

3=15x

3/15=x

•x=1/5

Answer 2

Answer :-

3/x + 4y = 7 ...(i)

5/x + 6y = 13 ...(ii)

By multiplication of 3 in equation (i) and

By multiplication of 3 in equation (i) and 2 in equation (ii)

→ 9/x + 12y = 21 ..(iii) .

→ 10/x + 12y = 26 ...(iv)

Now equation (iv) - (iii)

10/x + 12 y = 26

- 9/x -12y = 21

_________________

1/x = 5

So Value of x = 1/5

Now by putting Value of x in equation (i)

3 × 1/x + 4y = 7

3 × 5 + 4 y = 7

15 + 4y = 7

4 y = -8

y = -2 .

So Value of

x = 1/5

y = -2