Question

In the xy-plane, the line x+y=k, where k is a constant, is tangent to the graph of y=x^2+3x+1 what is the value of k?

Answer 1

How would one approach this problem

Answer 2

The derivative of a function represents the tangent line of its curve. This is the key to this problem.

Answer 3

How would someone apply that concept to the first equation given?

Answer 4

Or rather how would one set up the problem?

Answer 5

Well... The question said that the line y=k-x is the tangent of y=x^2+3x+1.. What do you think that means considering the concept I wrote above?

Answer 6

Y prime of x^2+3x+1 is equal to y= k-x ...?

Answer 7

Yep!

Answer 8

Oh !!! I know what I need to do. Thank you so much!

Answer 9

I am sure you do!!