Question

Solve the following systems of equations:

11x + 15y + 23 = 0

7x – 2y – 20 = 0

Answer 1

The given system of equation is

11x + 15y + 23 = 0 .........(i)

7x - 2y - 20 = 0 ...(ii)

From (ii), we get

2y = 7x - 20

`=> y = (7x - 20)/2`

Substituting y = `(70x - 20)/2`  in (i) we get

`11x + 15((7x - 20)/2) + 23 = 0` 

`=> 11x + (105x - 300)/2 + 23 = 0`

`=> (22x + 105x - 300 + 46)/2 = 0`

`=>  127x - 254 = 0`

=> 127x = 254

`> x = 254/127 = 2`

Putting 2 x = 2 in y = `(7x - 20)/2`  we get

`=> y = (7xx2-20)/2`

`= (14-20)/2`

`= -6/2`

= -3

Hence, the solution of the given system of equations is x = 2, y = -3