find the values of x at at which the curve f(x)=(3x-4)^7(x+5)^4 has a horizontal tangent line

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- October 15th 2008, 08:08 AMvinson24[SOLVED] horizontal tangent line
find the values of x at at which the curve f(x)=(3x-4)^7(x+5)^4 has a horizontal tangent line

- October 15th 2008, 08:59 AMvinson24
i know how to get two of the answers which are 4/3,-5 but the third answer -89/33 i dont know how to get

- October 15th 2008, 09:08 AMChris L T521
- October 15th 2008, 09:19 AMSoroban
Hello, vinson24!

I assume you know about horizontal tangents

and that it's the*algebra*that troubles you . . .

Quote:

Find the values of at at which the curve

has a horizontal tangent line.

Product Rule: .

We have: .

Factor: .

. . . . . .

. . . . . . . . . . . . . .

And we have: .

But please check*my*algebra . . .

.