Which of the following systems of equations has no solution?

A. 18x − 6y = 14; 3y = 9x − 7
B. 7x − 4 = 3y; 6y − 3 = 14x
C. 4x + y = 10; 2y = 8x − 2
D. -5y = x − 6; 3x − 15y = 9

Question

Which of the following systems of equations has no solution? 

    A. 18x − 6y = 14; 3y = 9x − 7 
    B. 7x − 4 = 3y; 6y − 3 = 14x 
    C. 4x + y = 10; 2y = 8x − 2 
    D.  -5y = x − 6; 3x − 15y = 9

anonymous · Answer

The way to go about doing this is to just manually solve every single option. It is tedious and simple at the same time....

A. 18x-6y = 14
3y = 9x - 7  => (times 2) 6y = 18x - 14
18x - (18x -14) = 14
14= 14 (all solutions of x and y)

B.  7x − 4 = 3y => (times 2) 14x- 8 = 6y
 6y − 3 = 14x 
(14x- 8) -3 = 14x
14x - 8 -3 = 14x
14x - 11 = 14x
-11 = 0 (no solutions)

Answer is B.

anonymous · Answer

attachment