SOLUTION: Find the pair of integers (a,b) for which 2^a+1 + 2^a = 3^b+2 - 3^b

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Question 1199909: Find the pair of integers (a,b) for which 2^a+1 + 2^a = 3^b+2 - 3^b
Found 3 solutions by greenestamps, MathTherapy, math_tutor2020:
Answer by greenestamps(13195) About Me  (Show Source):
You can put this solution on YOUR website!


Surely the equation as you show it is not correct; it has an infinite number of solutions.

2^a+1 + 2^a = 3^b+2 - 3^b ==> 2%5Ea%2B1%2B2%5Ea=3%5Eb%2B2-3%5Eb

2%282%5Ea%29%2B1=2

2%282%5Ea%29=1
2%5Ea=1%2F2
a=-1

SOLUTIONS: a=-1; b is any number

If you are working on a problem like this, your level of knowledge of math should be enough for you to know that proper use of parentheses is important.

Assuming the equation I have solved above is NOT the equation you intended, re-post the problem correctly....


Answer by MathTherapy(10549) About Me  (Show Source):
You can put this solution on YOUR website!
Find the pair of integers (a,b) for which 2^a+1 + 2^a = 3^b+2 - 3^b

If this is matrix%281%2C3%2C+2%5E%28a+%2B+1%29+%2B+2%5Ea%2C+%22=%22%2C+3%5E%28b+%2B+2%29+-+3%5Eb%29, then it SIMPLIFIES to the equation matrix%281%2C3%2C+2%5E%28a+-+3%29%2C+%22=%22%2C+3%5E%28b+-+1%29%29, 
and the integer-values for (a, b) = (3, 1).

Answer by math_tutor2020(3816) About Me  (Show Source):
You can put this solution on YOUR website!

I'm assuming the equation is
2%5E%28a%2B1%29%2B2%5Ea+=+3%5E%28b%2B2%29-3%5Eb
which is equivalent to writing out 2^(a+1)+2^a = 3^(b+2)-3^b
Use parenthesis for the exponents "a+1" and "b+2"

If my initial assumption is correct, then,
2%5E%28a%2B1%29%2B2%5Ea+=+3%5E%28b%2B2%29-3%5Eb

2%5Ea%2A2%5E1%2B2%5Ea+=+3%5Eb%2A3%5E2-3%5Eb Use the rule a^(b+c) = a^b*a^c

2%5Ea%2A2%2B2%5Ea+=+3%5Eb%2A9-3%5Eb

2%5Ea%2A%282%2B1%29+=+3%5Eb%2A%289-1%29

2%5Ea%2A%283%29+=+3%5Eb%2A%288%29

3%2A2%5Ea+=+8%2A3%5Eb

2%5Ea%2A%281%2F8%29+=+3%5Eb%2A%281%2F3%29

2%5Ea%2A2%5E%28-3%29+=+3%5Eb%2A3%5E%28-1%29

2%5E%28a-3%29+=+3%5E%28b-1%29

Because the bases are different, the two sides are only equal when the exponents are zero (to make both sides to simplify to 1).
a-3 = 0 leads to a = 3
b-1 = 0 leads to b = 1