Question

7x-2y/xy=5
8x+7y/xy=15
solve this any algebraic method substitution, elimination, Cross multiplication??plz solve this​

Answer 1

Answer:

X = 1 ,y = 1

Step-by-step explanation:

Given simultaneous equations:

(7x-2y)/xy = 5

=> 7x/xy - 2y/xy = 5

=> 7/y - 2/x = 5 ----(1)

and

(8x+7y)/xy = 15

=> 8x/xy + 7y/xy = 15

=> 8/y + 7/x = 15 ----(2)

Let 1/x = a , 1/y = b

Then ,

The equations becomes,

7b-2a=5 -----(3)

8b+7a=15 -----(4)

Now ,

multiply equation (3) by 7, and

equation (4) by 2, we get

49b-14a = 35 ----(5)

16b+14a=30-------(6)

Add equations (5) and (6), we

get

65b = 65

=> b = 65/65

=> b = 1

substitute b=1 in equation (3),

we get

7b - 2 = 5

=> 7b = 5+2

=> b = 7/7

=> b = 1

Therefore,

a = 1 => 1/x = 1 => x = 1

and

b=1 => 1/y = 1 => y = 1

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