SOLUTION: Hello, I have another question from my practice math exam, please help! (8)^2/3 (16)^1/4= -Thanks Kristin

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: Hello, I have another question from my practice math exam, please help! (8)^2/3 (16)^1/4= -Thanks Kristin      Log On


   



Question 31240: Hello,
I have another question from my practice math exam, please help!
(8)^2/3 (16)^1/4=
-Thanks
Kristin

Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
+%288%29%5E2%2F3 means either +%288%5E2%29%5E%281%2F3%29+ or +%288%5E%281%2F3%29%29%5E2+. You can solve either. However, the first version has 8%5E2 which is 64 then we need to find a cube root of that etc... Going the way of "increasing the numbers" is more difficult.

My approach would always be to do the fractional power first if possible, to keep the numbers smaller:
+%288%5E%281%2F3%29%29%5E2+
since 2*2*2 = 8
--> +2%5E2+
--> 4

%2816%29%5E1%2F4 means what number multplied to itself 4 times is 16? Answer is 2:
2*2*2*2 = 16

You need to recognise the following, in relation to powers:

2: 2,4,8,16,32,64,128,256,512,1024
3: 3,9,27,81
4: 4,16,64
5: 5,25,125,625
6: 6,36,216
7: 7,49,343
8: 8,64,512
9: 9,81,729

Recognise these numbers at least. Learn them if possible. That way you can answer the following type of Q really confidently:

+343%5E%282%2F3%29+ means +%28343%5E%281%2F3%29%29%5E2+ --> +7%5E2+ --> 49

jon.