Question

solve the wuestion by elimination method 3x-4y=11,7x-5y=4​

Answer 1

Given equations :

3x - 4y = 11 .....( 1 )

7x - 5y = 4 .......( 2 )

Multiply ( 1 ) by 5 and ( 2 ) by 4, we get

5 ( 3x - 4y ) = 5 ( 11 )

→ 15x - 20y = 55

And

4 ( 7x - 5y ) = 4 ( 4 )

→ 28x - 20y = 16

Now, Subtract both the new formed equations, we get

( 15x - 20y ) - ( 28x - 20y ) = 55 - 16

15x - 20y - 28x + 20y = 55 - 16

- 13x = 39

x = - 39/13

x = - 3

Put this value in ( 1 ), we get

3 ( - 3 ) - 4y = 11

- 9 - 4y = 11

- 4y = 11 + 9

- 4y = 20

y = - 20/4

y = - 5

Hence, x = - 3, y = - 5

______Elimination Method______

In this method, the coefficients of one variable in both equations has to be same, so that it can be easily eliminate by addition or subtraction.