Find the gradient of y=x^2-6x-16 at the point where the curve crosses the x-axis
So we have y = 0 and therefore x2 - 6x - 16 =0
This is then factorised to (x+2)(x-8) = 0 and therefore we have x = -2, x = -8
To find the gradient we need to find dy/dx
So dy/dx = 2x - 6
Therefore if x = -2, And if x = 8
dy/dx = 2(-2) - 6 = -10 dy/dx = 2(8) - 6 = 10
HK
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