The function
F(x)=-a^x+4
will never cross the x-axis.
A. True
B. False

Question

The function
F(x)=-a^x+4
will never cross the x-axis.
 		A.	True
 		B.	False

anonymous · Answer

Set the function equal to 0 and see if you can find any solutions.

anonymous · Answer

no?

anonymous · Answer

Show some work so I can say yes or no to that.

anonymous · Answer

-a^x+4=0
i dont get what to do with the -a^x
i just assumed it was impossible

anonymous · Answer

np.  There are a couple ways to proceed on this, and you can choose depending on whether you are more analytical or more intuitive.  You can can continue on with 4 = a^x and go the way of logarithms for the analytical approach, solving for x.  Or you can "jump" to an intuitive approach and substitute for "a" with a couple easy to use smal positive and small negative integers and try to make an equation which is easy to use that might cross the x-axis.

anonymous · Answer

Remember, you only need one example to show "false" but you have to show a general principle to prove "true".