Asked by Alexandra
Find all real numbers x satisfying the equation:
2^x + 3^x - 4^x + 6^x - 9^x = 1.
Please help me. I really don't know what to do.
2^x + 3^x - 4^x + 6^x - 9^x = 1.
Please help me. I really don't know what to do.
Answers
Answered by
Steve
Hmm. It's clear that x=0 works, but is there anything else?
(2^x+1)(3^x+1) = 2^x + 3^x + 6^x + 1
so,
(2^x+1)(3^x+1) +1-4^x + 1-9^x = 4
(1+2^x)(1+3^x) + (1+2^x)(1-2^x) + (1+3^x)(1-3^x) = 4
(1+2^x)(1+3^x+1-2^x) + (1+3^x)(1-3^x) = 4
I don't see anything dropping out. If we can show that 1 is the maximum value of the function, then there is probably no other solution. Can't see right off how to show that, either. There's probably some clever trick involved.
(2^x+1)(3^x+1) = 2^x + 3^x + 6^x + 1
so,
(2^x+1)(3^x+1) +1-4^x + 1-9^x = 4
(1+2^x)(1+3^x) + (1+2^x)(1-2^x) + (1+3^x)(1-3^x) = 4
(1+2^x)(1+3^x+1-2^x) + (1+3^x)(1-3^x) = 4
I don't see anything dropping out. If we can show that 1 is the maximum value of the function, then there is probably no other solution. Can't see right off how to show that, either. There's probably some clever trick involved.
Answered by
Alexandra
Thanks, I already know that 0 is the answer but I don't know how to arrive to that. Huhu, I don't know the solution. Please help me, thanks.
Answered by
Sharon
A basketball player scored 26 times during a game. He scored a total of 45 points, 2 for each field goal and 1 for each free throw. How many 2 point shots did he make and how many free throws?
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