Question

3/x+4y=7 5/x+6y=13 solve by cross multiplication method​

Answer 1

☢ Given:

• 3/x+4y=7

• 5/x+6y=13

☢ Solution:

Let 1/x = u and 1/y = v

∴ 3u + 4v = 7      (1)

and 5u + 6v = 13    (2)

Multiplying (1) by 5 and (2) by 3; we get:

15u + 20v = 35     (3)

15u + 18v = 39      (4)

Subtracting (4) from (3)

2v = -4

⇒ v = -2

Putting in (1) we get:

u = 5

⇒  x = 1/5, y = -1/2

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