Data Sufficiency (DS) | Re: How many intersects with x-axis does y = x^2 + 2qx + r have ?

HiTheMastermind ,

Here I go.

For this question, you need to understand two things:

1. If the equation is intersection x axis, then y must be zero. Or I can say\(x^2\) + 2qx + r = 0
2. Roots of a quadratic equation(\(ax^2 + bx + c = 0\) are given by the formula:

x =\([ -b + \sqrt{b^2 - 4ac}]/2a\)

and

x =\([ -b - \sqrt{b^2 - 4ac}]/2a\)

Now, in order to have real roots, the values inside the square root MUST be positive.

or I can say\( b^2 - 4ac >\)
...

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