Question

show that x = 3 and Y = 2 is not a solution of the system of simultaneous linear equations 3x+4y=17 and 4x-3y=12​

Answer 1

Given : linear equations are ; 3x + 4y = 17 and 4x - 3y = 12.

To show : x = 3 and y = 2 is not a solution of the system of simultaneous linear equations 3x + 4y = 17 and 4x - 3y = 12.

solution : solve the equations

3x + 4y = 17. .........(1)

and 4x - 3y = 12. ............(2)

multiplying 3 with equation (1) and 4 with equation (2) and adding both equations.

i.e., 3(3x + 4y) + 4(4x - 3y) = 3 × 17 + 4 × 12

⇒9x + 12y + 16x - 12y = 51 + 48 = 99

⇒25x = 99

⇒x = 99/25

now putting x = 99/25 in equation (2) we get,

4(99/25) - 3y = 12

⇒396/25 - 12 = 3y

⇒96/25 = 3y

⇒y = 32/25

here x = 99/25 ≠ 3 and y = 32/25 ≠ 2

Therefore x = 3 and y = 2 is not a solution of the system of simultaneous linear equations 3x + 4y = 17 and 4x - 3y = 12.