Question

2x+3y=7 and 3x+2y=3, then x-y=......,select a proper option (a), (b), (c) or (d) from given options so that the statement becomes correct.
(a) 4
(b) -4
(c) 2
(d) -2

Answer 1

2x+3y=7 & 3x+2y=3

Multiplying equation 1 with 3 and equation 2 with 2 gives,

6x+9y=21

6x+4y=6

Subtracting these two equations gives that 5y=15 =>y=3

6x+9y=21

=>6x+27=21

=>x=-1

=> x-y = -1 - 3 = -4

Ans(b)-4.

Answer 2

Option ( b ) is correct.

Explanation :

Given pair of linear equations ,

2x + 3y = 7 ---( 1 )

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


[ 3 × ( 1 ) - 2 × ( 2 ) ], we get

6x + 9y = 21

6x + 4y = 6
___________
*******5y = 15

=> y = 15/5

=> y = 3

Put x = 3 in equation ( 1 ) ,we get

2x + 3×3 = 7

=> 2x + 9 = 7

=> 2x = 7 - 9

=> 2x = -2

=> x = ( -2 )/2

=> x = -1

Therefore ,

x - y =

= -1 - 3

= -4

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