# Equation query

## Homework Statement

(3.4)^2x+3 = 8.5. Solve for x

## The Attempt at a Solution

3.4^2x = 8.5/3.4^3 ( divide the equation by 3.4^3. This bit i am not sure about)

2xlog3.4 = log (8.5/3.4^3

x = log (8.5)- 3log(3.4) / 2 log (3.4)

=0.929-1.594/1.063
x = -0.626

This seems to work out when i plug it in to the original equation.
Is there an insert equation icon on the template. Can`t find it!

## Answers and Replies

jedishrfu
Mentor
I think you meant to say:

(3.4)^(2x+3) = 8.5. Solve for x.

Right? If not you need to edit your post to fix it.

What do you mean by "an insert equation icon"?

Looked at the question again and I have wrote it correctly. 3.4 is in parentheses. Not sure why this is so.

An equation icon makes my equations look neater if you know what I mean!

haruspex
Science Advisor
Homework Helper
Gold Member
Looked at the question again and I have wrote it correctly.
Are you saying that the original looks exactly like that, using the caret symbol instead of a superscript? Seems unlikely, so what you have posted is probably a rendition. But what you posted is equivalent to 3.42x+3. If you meant 3.42x+3 then you can write it as 3.4^(2x+3). And I feel it is a little simpler to take logs first then solve 2x+3 = log(8.5)/log(3.4).

• jedishrfu
Apologies jedishrfu, I have wrote it down wrong. Thanks haruspex, I should have used parentheses after the caret symbol. You live and learn!!