SajjadAhmad wrote:
If the curve described by the equation y = x^2 + bx + c cuts the x-axis at -4 and y axis at 4, at which other point does it cut the x-axis?
A. -1
B. 4
C. 1
D. -4
E. 0
Given, \(y = x^2 + bx + c\), cuts the x-axis at two points. One intersection point with x-axis is given. We need to find out the other point of intersection. In other words, 1 root of the quadratic equation is given, what is the value if the other root?
a) At (-4,0), \(0=(-4)^2+b*(-4)+c\) Or, 4b-c=16
b) At (0,4), \(4=0^2+b*0+c\) Or, c=4
So, 4b-4=16 Or, b=5.
Now, we have the equation of the curve, \(y=x^2+5x+4\), which has the roots: -4 and -1.
So, other other root is -1.
Ans. (A)
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PKN
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