# Math Help - finding tangent line

1. ## finding tangent line

find an equation of the tangent line at the given point P.

y= 3x^2 + 5x -7, P(-2, -5)

2. Originally Posted by teresa
find an equation of the tangent line at the given point P.

y= 3x^2 + 5x -7, P(-2, -5)
step 1 ... find $y'(x)$

step 2 ... using $y'(x)$, find the value of the slope of the curve at point P, i.e. $y'(-2)$

step 3 ... using the slope found in step 2 and the coordinates of the given point P, use the point-slope form of a linear equation to find the equation of the tangent line.

$\textcolor{red}{y - y_1 = m(x - x_1)}$