Question

if x/a + y/b = 1 and x = y = 2b = 3, find a

Answer 1

Answer:

Step-by-step explanation:

Given, x=a and y=b.

Given equations, x-y=2( assume it as equation 1)

x+y=4( assume it as equation 2)

Equation 1+2,

x-y=2

x+y=4

- - - - - - -

2x=6( y gets cancelled as there is a negative y and a positive y implies y-y=0)

x=6/2

x=3

But x=a implies a=3

substitute a in equation 1 (it can be substituted even in equation 2)

x-y=2

3-y=2

y=3-2

y=1

But y=b implies b=1

Therefore, a=3 and b=1

Answer 2

Given,

$\bold{x=y=2b}$

Given equation,

$\bold{\frac{x}{a}+\frac{y}{b}=1}$

Applying the value of y(= 2b) to the equation,

$\implies\bold{\frac{x}{a}+\frac{2b}{b}=1}$

$\implies\bold{\frac{x}{a}+2=1}$

$\implies\bold{\frac{x}{a}=1-2}$

$\implies\bold{\frac{x}{a}=-1}$

Given, x = 3

$\implies\bold{\frac{3}{a}=-1}$

$\implies\bold{a=\frac{3}{-1}}$

$\implies\bold{a=-3}$

$\boxed{\bold{\therefore a=-3}}$