ax2 + bx + c intersect y-axis

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ax2 + bx + c intersect y-axis

by Shalabh's Quants » Fri Apr 13, 2012 7:26 am
If f(x) = ax2 + bx + c, and a is not equal 0. At what point does the graph of the function f(x) intersect the y-axis?

1.The graph of f(x) intersects the x-axis exactly twice, at (-6, 0) and (-2, 0)

2.a = 2
Shalabh Jain,
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by killer1387 » Fri Apr 13, 2012 7:48 am
Shalabh's Quants wrote:If f(x) = ax2 + bx + c, and a is not equal 0. At what point does the graph of the function f(x) intersect the y-axis?

1.The graph of f(x) intersects the x-axis exactly twice, at (-6, 0) and (-2, 0)

2.a = 2
f(x) = ax2 + bx + c;
f(0)= c=?

1) 36a-6b=-c
4a-2b=-c
2a-b=18a-3b
=>2b=16a
=>b= 8a

Insufficient

2)a= 2

Insufficient

1&2

a= 2
b= 16
c= 24

Sufficient

Hence C