Question

Solve the following systems of equations:

`4/x + 15y = 21`

`3/x + 4y = 5`

Answer 1

The given system of equation is

`4/x + 15y = 21` ....(i)

`3/x + 4y = 5` ....(ii)

Multiplying equation (i) by 3 and equation (ii) by 4, we get

`12/x + 15y = 21`   .....(iii)

`12/x + 16y = 20` .....(iv)

Subtracting equation (iii) from equation (iv), we get

`12/x - 12/x + 16y - 15y = 20 - 21`

y = -1

Putting y = -1 in equation (i) we get

`4/x + 5xx (-1) = 7`

`=> 4/x - 5 = 7`

`=> 4/x = 7 + 5`

`=> 4/x = 12`

=> 4 = 12x

=> 4/12 = x

`=> x = 4/12`

`=> x = 1/3`

Hence, solution of the given system of equation x = 1/3, y =- -1