TI 86 help
 

I suppose this is a very simple thing to do, yet for the life of me I cannot figure it out. I've searched about 20 different websites, read the manual and still cannot figure it out.

I need to know how to graph equations like 3^x=21 while solving for x. I need the x-intercept from the graph on the caculator.

So far this is what I have:

'graph'
y(x)
\y1=[equation here]

However I don't think that is correct.

Anyone?

I hope you're not trying to find the x-intercpt of y=3^x.

I'm working with a TI85, so it might be a tad different, but that should work. y1=3^x will get you a graph.

I'm having trouble seeing how to get the x intercept (assuming it were an equaion with an x intercept). Y intercept is easy. I'll see what I can figure out.

Okay, this seemed to work, don't ask me why.

Once you have your graph, select "Math" from the function menus (should be the f1 key after you hit "more"). Then select "Root" (should be f3). Move the cursor to just left of the x-intercept and press enter. It should display the x-intercept (point where y=0) at the bottom of the screen.

I'll ask Tori. Brb.;)

D'OH! I forgot to post an update. I figured out how to do this problem..

But now I have an even more complicated problem to do

5^(-x+3)=91. When I enter it I get an error. Sigh. I hate math.

Thank you everyone in advance for your help!

I can help with 1+1=2

Tori wants to know why you are cheating....lol.

(I told her I thought this was for school).

Eww, math.

Tell Tori that in college you are allowed to use fancy smancy caculators to help you with your math. In fact these problems say "with a graphing caculator find....". :D

Lol- no way! She'll expect to be able to do so, too!