How would I use the graph to solve this?

Question

I am to use a graph to solve 8=3^x.

Any help would be appreciated. I know you can't necessarily graph but explanations would help. Please explain completely as possible so that I can learn the concept and do similar problems on my own. Thanks so much and 10 points to the best answer!

Answer 1

You can solve ANY equation graphically by graphing the left hand side and the right hand side separately, and then finding the point(s) of intersection.  These x-values will be the solutions to the equation.

You can graph Y1 = 8, and Y2 = 3^x

The x-coordinate of the intersection will be the solution.

Or, you can set the entire equation equal to 0, and then find where it crosses the line y = 0

Y1 = 8 - 3^x  (or 3^x - 8, it doesn't matter)

Y2 = 0

again, find the intersection (it's quicker to do this on most calculators than to find the zeros-- you don't have to set bounds on the solution for intersections like you do for zeros)

Answer 2

Your solution would be when the two graphs intersect each other (when they're equal). The x coordinate of that point is your answer.

If you have a graphics calculator, you can simply graph these and using the technology, find the intersection point.

Answer 3

graph the equation y=3^x-8 in a calculator or by hand, and then see where it crosses the x axis.

make it a good day

Answer 4

Watch where lines intercept.