Question

Find the value of x- y for the following equations: 2x + 3y = 3

and

and

7x + 2y = 27

3x + 2y = 7​

Answer 1

2x+3y = 3 -----------> (1)

7x+2y = 27 ------------> (2)

3x+2y = 7 ---------------> (3)

Then,

2x+3y = 3

x= 3-3y/2 ----------> (4)

Now ,(4) substitute in (3)

3(3-3y/2)+2y = 7

9-9y/2+2y = 7

9-9y+2y =7×2

9-7y = 14

-7y = 14-9

-7y = 5

y = -5/7 --------> (5)

Then,

(5) substitute in (1)

2x+3(-5/7) = 3

2x+(-15/7) = 3

2x-15/7 = 3

2x-15 = 3×7

2x-15 = 21

2x = 21+15

2x = 36

x= 36/2

= 18

Now, x = 18

y = -5/7

x-y = 18-(-5/7)

= 18+5/7

= 126+5/7

= 131/7

= 78.71..