jamesk486 wrote:In the xy plane, at what two points does the graph of y= (x+a)(x+b)
(1) a+b=-1
(2) the graph intersects the x=axis at at (0,6)
can someone pls pls help me out?
Is statement (2) given correctly. I can't visualize a graph
cutting the x-axis at (0,6). If a graph cuts the x-axis, the y intercept
has to be zero. In this case, y = 6 ??
I recall seeing this question on gmat-prep when I took the test and if
I recall correctly, it was something along the lines of
1 - insufficient. We just know a+b=-1. We need to find a and b since
these are the 2 points at which the graph cuts the x-axis
2 - insufficient. We just know ab=6 (substitute for x, y in eqn)
Together we can find a and b and hence is sufficient.
Answer is C.
