LOGS: maths question - solve for x: 3^(x+2) = 3^x + 216?

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LOGS: maths question - solve for x: 3^(x+2) = 3^x + 216?

i cant solve this question and its been bugging me
please help!

solve 3^(x+2) = 3^x + 216 for x.

3 to the power of (x+2) = 3 to the power of x plus 216.

2007-11-26 06:12:47 · 2 answers · asked by PeterW 1 in Science & Mathematics ➔ Mathematics

2 answers

3^(x+2) = 3^x + 216
=> 9(3^x) = 3^x + 216
=> 8(3^x) = 216
=> 3^x = 27 = 3^3
=> x = 3

2007-11-26 06:23:19 · answer #1 · answered by sahsjing 7 · 0⤊ 0⤋

3^x * 9 -3^x=216

8 * 3^x=216

3^x=216/8

3^x=27=3^3

x=3

2007-11-26 14:22:07 · answer #2 · answered by iyiogrenci 6 · 0⤊ 0⤋