Hey guys and gals.

I was wondering if I could get some help with a question that reads.

Determine the x-intercepts of the curve which has a slope 2x +1 and passes through (1, -4)

Thank You so much!

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- Mar 16th 2009, 08:33 PMMeeklo BracaDetermining x-intercepts of a curve
Hey guys and gals.

I was wondering if I could get some help with a question that reads.

Determine the x-intercepts of the curve which has a slope 2x +1 and passes through (1, -4)

Thank You so much! - Mar 16th 2009, 10:06 PMProve It
If it has a slope of $\displaystyle 2x + 1$ then we can say

$\displaystyle \frac{dy}{dx} = 2x + 1$.

Therefore

$\displaystyle y = \int{2x + 1\,dx}$

$\displaystyle y = x^2 + x + C$.

We're told that $\displaystyle (1, -4)$ lies on the curve, so

$\displaystyle -4 = 1^2 + 1 + C$

$\displaystyle -4 = 1 + 1 + C$

$\displaystyle -4 = 2 + C$

$\displaystyle -6 = C$.

Thus $\displaystyle y = x^2 + x - 6$.