Question

Which equation has (2,-1) as a solution?
Y=2x-1
Y=x+3
Y=x-3
y=-2x+1

Answer 1

2 and -1 are the roots of the equation right?

Answer 2

Yes

Answer 3

Okay so its pretty difficult to explain, but (x,y) < That is how it is. So if its

(2,-1)

X=2 Y=-1

And now replace with x as well.
Now we have to see which one of these equations = -1
So we have to replace and solve:
-1=2*2-1=3 ~False
-1=2+3 = 5 ~False
-1=2-3 = -1 ~True
-1=-2*2+1=5 ~False


Answer: -1=2-3
Therefore: C