Value of Exponent

What is the value of x if 4^{20}+4^{20}=2^x?
Source: NCTM Mathematics Teacher, January 2006

SOLUTION
4^{20}+4^{20}=2^x
4^{20}(1+1)=2^x
4^{20}(2)=2^x
(2^2)^{20}(2)=2^x
2^{40}(2)=2^x
2^{41}=2^x
x=41

Answer: 41

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About mvtrinh

Retired high school math teacher.
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