For the curve y = (1/3)x^3, given that 24x + 3y +2 = 0 is the equation of the tangent to the curve at the point (p,q) find p and q.(adsbygoogle = window.adsbygoogle || []).push({});

I rearranged to get y = -8x - 2/3

So the tangent gradient is -8

I differentiated to get x^2 - 9

Therefore x^2 - 9 = -8 and x = 1 or x = -1.

From here how do I distinguish whether x = 1 or x = -1?

Many thanks.

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# Homework Help: Geometry problem

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