Question

Solve the following linear equation
11x+15y+23=0
7x-2y-20=0

Answer 1

Step-by-step explanation:

1st equation multiply by 7

2nd multiply by 11

subtracted

77x+105y+161=0

77x-22y-220=0

-. +. +

127y+381=0

y=-381/127=-3

y=-3

substitute y in 2nd equation

7x+6-20=0

x=2

Answer 2

$\Large{\textbf{\underline{\underline{According\;to\;the\;Question}}}}$

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

7x - 2y - 20 = 0

From (a) we have,

11x + 15y + 23 = 0

11x + 15y = -23……. (1)

Also,

7x - 2y - 20 = 0

7x - 2y = 20 ………. (2)

From (2),

-2y = (-7x + 20)

2y = 7x - 20

y = (7x - 20)/2 ………..(3)

Putting value of y in (1),

11x + 15y = - 23

11x + 15(7x - 20)/2 = -23

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

(11x × 2 + 105x - 300)/2 = -23

22x + 105x - 300 = -23 × 2

22x + 105x - 300 = -46

22x + 105x = -46 + 300

127x = 254

x = 254/127

x = 2

So,

Substituting value of x in (3),

y = (7x - 20)/2

y = (7 × 2 - 20)/2

y = (14 - 20)/2

y = -6/2

y = -3

Therefore,

x = 2 and y = -3