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I need help for two questions to solve 4^3x=8 & 4^2x=7 by graphing?

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You have to make a list of x and y values. 

1) For your first equation (y = 43x) you will have

                              x    0     1/3     1/2     1

                              y    1      4         8      64

Since  43x = 8 your anwerr is x = 1/2.  For the right side y = 8 - horizontal line intersecting y=43x 

at x = 1/2.

2)  The same way, for the second equation you can make a chart

                                    x    0    1/4     1/2      1

                                    y    1     2        4       16

Since the right side is y =7, function y = 42x will intersect y = 7 line at   1/2 < x <1. If you solve it analytivally (by taking logarithms) you will find that  in this case x = 0.702  (x = ln7/2ln4). Use the numbers shown to sketch the graph to make sure that x = 0.702. Good luck!