5y = -x + 4; 3x + 15y = 12

Rewrite the second equations into the same form as the first ones:

5x + 5y = 11; 10y = 10x − 22

Subtract 10x from both sides of the second equation:

-10x + 10y = -22

Since the x and y signs are opposite, the equations are not the same

8x − 3 = 6y; 12y − 6 = 4x

Add 6 to both sides and flip it around:

4x + 6 = 12y

Since the constant's signs are opposite, the equations can't be the same.

5x − 7y = 4; 14y = 10x + 8

Subtract 10x from both sides:

14y - 10x = 8

Divide through by -2:

-7y + 5x = -4 or 5x - 7y = -4 That's close to the first but not the same.

5y = -x + 4; 3x + 15y = 12

Subtract 3x from both sides:

15y = -3x + 12

Divide through by 3:

5y = -x + 4 (same equation, infinite solutions)

Who cares? Go get some ice cream and watch TV.

just look at the slopes, the third pair has the same slope so it's probably (99.99999997%) the answer