In the xy coordinate plane, at what two points does the line y=(x+a)(x+b) intersect the x-axis?
a. a+b=-1
b. the graph intersects the y-axis at (0,-6)
Whats the ans ?
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Confusing coordinates
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parallel_chase
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y=(x+a)(x+b)Sandman wrote:In the xy coordinate plane, at what two points does the line y=(x+a)(x+b) intersect the x-axis?
a. a+b=-1
b. the graph intersects the y-axis at (0,-6)
Whats the ans ?
Statement I and II are clearly insufficient.
x^2+ax+bx+ab
a+b = -1
ab = -6 [from second statement]
x^2 - x -6 = 0
(x-3)(x+2) =0
Therefore the two points are
(3,0) and (-2,0) because in both cases we know that y has to be 0.
Hope this helps.
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parallel_chase
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y intercept will always be 0 when a line intersects at x axis.Sandman wrote:Thanx for the reply...but how did u get x^2-x-6=0 after combining the two statements..shouldnt it be x^2-x-6=y ? Sorry but i dint get the last part where u calculated the two pts..Can u explain that plz.
