Question

1/a+2/b=5 and 2/a+1/b=3 then find a-b/ab​

Answer 1

Answer:

hope this is helpful to you

thanks!

Answer 2

$Given \:\frac{1}{a} + \frac{2}{b} = 5 \: ---(1)$

$\frac{2}{a} + \frac{1}{b} = 3 \: ---(2)$

$Let \: x = \frac{1}{a} \:and \:y = \frac{1}{b}$

/* Then , the equations (1) and (2) , becomes */

$x + 2y = 5 \: ---(3)$

$2x + y = 3 \: ---(4)$

/* Subtract equation (4) From 2× [Equation (3) ], we get */

$\implies 3y = 7$

$\implies y = \frac{7}{3} \: --(5)$

/* Substitute value of y , in equation (3) ,we get */

$x + 2 \times \frac{7}{3} = 5$

$\implies x + \frac{14}{3} = 5$

$\implies x = 5 - \frac{14}{3}$

$\implies x = \frac{15 - 14}{3}$

$\implies x = \frac{1}{3}\: --(6)$

$x = \frac{1}{3} = \frac{1}{a }$

$\implies a = 3$

$y = \frac{7}{3} = \frac{1}{b}$

$\implies b = \frac{3}{7}$

Therefore.,

$Value \: of \: \frac{a-b}{ab} \\= \frac{3 - \frac{3}{7}}{ 3 \times \frac{3}{7}}\\= \frac{\frac{21-3}{7}}{\frac{9}{7}}\\= \frac{18}{9} \\= 2$

$\red{Value \: of \: \frac{a-b}{ab}}\green { = 2}$

•••♪