Q:

Is 2 , -5 a solution to this system equation 2x + 5y = -19, 6y - 8x = -54 .? Justify your answer

Accepted Solution

A:
The easiest way to solve this problem is to put (2, -5) into both equations and see if it satisfies/works for both of them. 2 = x and -5 = y.

So for 2x + 5y = -19, 
2(2) + 5(-5) = -19
4 - 25 = -19
-21 ≠ -19.

You can continue and try it out for 6y - 8x = -54 
6(-5) - 8(2) = -54
-30 - 16 = -54
-46 ≠ -54

But since (2, -5) already doesn't work for one equation, it cannot be a solution to the system of equations.