Question

Solve 3x+2y=11;2x+3y=4 by the method of substitution and Elimination method

Answer 1

Answer:

By substitution method

2x + 3y = 4

2x = 4 - 3y

x = 4 - 3y / 2 ------> equation 1

3x + 2y = 11

putting the value of x from equation 1 , we get

3 ( 4 - 3y / 2 ) + 2y = 11

( 12 - 9y ) / 2 + 2y = 11

( 12 - 9y + 4y ) /2 = 11

12 - 5y = 22

-5y = 10

y= -2

Putting the value of y in equation 1 we get

x = ( 4+6 ) /2

x = 10/2

x = 5

Hence , we got x=5 and y=-2

By elimination method

( 2x + 3y= 4 ) × 3

6x + 9y = 12 -----> equation 1

( 3x + 2y = 11 ) × 2

6x + 4y = 22 -------> equation 2

subtract equation 1 from equation 2

6x + 9y. =. 12

6x. +. 4y. =. 22

-. -. -

____________

5y =. -10

y = -2

Putting the value of y in equation 1 we get

6x + 9*(-2) = 12

6x - 18 = 12

6x = 30

x = 5

Hence , we got x=5 and y=-2

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