Question

4/x+7/y=18 and 2/x+1/y=6 find value of 1/x+1/y=?

Answer 1

Let 1/x be 'p' and 1/y be 'q'.
So, 4p + 7q = 18 ....(1)
2p + q = 6 ....(2)

(1) - (2),

(1) = 4p + 7q = 18
(2) * 2 = 4p + 2q = 12 (-)
Ans. = 0 + 5q = 6

5q = 6
q = 6/5
1/y = 6/5 ....(3)

Applying (3) in (2),
2p + 6/5 = 6
2p = 6 - 6/5
2p = (30 - 6)/5
2p = 24/5
2p * 5 = 24
10p = 24
p = 24/10
p = 12/5
1/x = 12/5

Hope it Helped!

Answer 2

Hi ,

4/x + 7/y = 18 ----( 1 )

2/x + 1/y = 6 ------( 2 )

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

4a + 7b = 18 -----( 3 )

2a + b = 6

b = 6 - 2a ----( 4 )

put b value in equation ( 3 ) , we get

4a + 7( 6 - 2a ) = 18

4a + 42 - 14a = 18

- 10a = 18 - 42

- 10a = - 24

a = ( -24 ) / ( - 10 )

a = 12/5

put a = 12/5 in equation ( 4 ) , we get

b = 6 - 2 ( 12/5 )

= 6 - 24/5

= ( 30 - 24 ) /5

b = 6/5

Therefore ,

a = 12/5 , b = 6/5

1/x = 12/5 , 1/y = 6/5

1/x + 1/y = 12/5 + 6/5

= ( 12 + 6 ) /5

= 18/5

I hope this helps you.

:)