M8 wrote:

In the xy-plane, at what two points does the graph of y=(x+a)(x+b) intersect the x-axis?

1) a+b=-1

2) The graph intersects the y-axis at (0;6).

Please explain. Thank you.

st. 1

Insuff, because infinite number of possibilities..

st. 2

y=x^2+(a+b)*x+a*b

if y-intersects at (0,6), then a*b = 6.

so equation is not --> y=x^2+(a+b)*x+6

before I try to combine st. 1, I know that the parabola is going to open up. I feel that this is Insuff.

combine both:

I get y=x^2-1*x+6, but this does not have integer roots for X...

so by the combination of both, it does not intersect the x-axis.

C is my answer... but would E work here?