Unsolvable problem?

3^x = 4x + 15

Here's the farthest I can get:

log(3^x) = log(4x + 15)

xlog(3) = log(4x + 15)

x = log(4x + 15)/log(3)

Is graphing and finding the intersection point the only way to solve this?

To my knowledge, this equation cannot be solved algebraically. You will have to use other methods. Sorry! (Blush)

Quote:

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Originally Posted by stapel

To my knowledge, this equation cannot be solved algebraically. You will have to use other methods. Sorry! (Blush)

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Same, you'd need to iterate upon a solution.

3^x = 4x + 15

I plotted this graph (see below) and roughly arrived at x = -3.75 and x = 3.00.

x = 3 is a solution but I got this from looking at the graph (Blush)