# equations of tangents and normals

posted by
**elle** on
.

hi, i'd really appreciate some help solving this question! I am completely at loss here :/ The question is to:

Find the equation of the normal to y=loge(x+2) which is parallel to the line with equation y+3x-5=0

I am fine at solving these sorts of equations when they give me one equation and an provide a given x value but in this question i have no idea what i am meant to be doing... Please help!!

Put the second equation in slope intercept form

y=-3x +5 slope is -3

So what is the slope of the tangent to

y=ln(x+2)

slope= 1/(x+2)

so the inverse negative slope will be

- (x+2), this has to equal -3x

set them equal, and you have the x where it occurs.

Put that x into the log equation, and find y.

y=mx +b

You have y, m, x, solve for b.