Question

Solve the following simultaneous equation by elimination method:
y = 8 – 3x ; x + 5y = -2

Answer 1

Given

y = 8 - 3x (i)

x + 5y = -2 (ii)

To find

x and y by using Elimination method

First of all take (i)

y = 8 - 3x

3x + y = 8 (i)

We have

3x + y = 8 (i)

x + 5y = -2 (ii)

Now we have to eliminate x , so multiply by 1 in (i)st equation and Multiply by 3 in (ii)nd equation

3x + y = 8 (i) × 1

x + 5y = -2 (ii) × 3

3x + y = 8 (i)

3x + 15y = -6 (ii)

Subtract (ii)eq from (i)eq

3x + y - (3x + 15y) = 8 - (-6)

3x + y - 3x - 15y = 8+6

-14y = 14

y = -1

Now put the value of y = -1 in (ii)eq

x + 5y = -2 (ii)

x + 5(-1) = -2

x - 5 = -2

x = 5-2

x = 3

Answer

x = 3 and y = -1

Answer 2

Answer:

(x+5y=-2)×6

(3x+y=8)×2

6x+30y=-12

6x+2y=16

28y=28

y=28/28

y=-1