Question

4/x+5/y=7;3/x+4/y=5​

Answer 1

Step-by-step explanation:

put 1/x=u & 1/y=v

4u+5v=7 ....(1)

3u+4v=5.......(2)

multiply ...(2) by 4 .........12u+16v=20

multiply ...(1) by 3 .........12u+15v=21

subtract above equations and we get

v=-1

then putting value of v in ....(1) we get,u=3

Thus ,x=1/3 and y=-1

Answer 2

Step-by-step explanation:

$\frac{4}{x} + \frac{5}{y} = 7 \\ \frac{3}{x} + \frac{4}{y} = 5$

$let \: \frac{1}{x} = u$

$\frac{1}{y} = v$

so the equation will be

$3(4u + 5v = 7) \\ 4(3u + 4v = 5)$

$12u + 15v = 21 \\ 12u + 16v = 20$

so the values we get!

$v = - 1 \\ u = 3$

so the values of x and y will be

$\frac{1}{x} = u \\ \frac{1}{x} = - 1 \\ x = - 1$

$\frac{1}{y} = v \\ \frac{1}{y} = 3 \\ y = \frac{1}{3}$