SOLUTION: If 2^y=10, find the value of 8^(2y-1)

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Question 1186695: If 2^y=10, find the value of 8^(2y-1)
Found 2 solutions by MathLover1, ikleyn:
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

If 2%5Ey=10, find the value of+8%5E%282y-1%29
first find y
2%5Ey=10....take log of both sides
log%282%5Ey%29=log%2810%29
y%2Alog%282%29=1
y=1%2Flog%282%29

substitute in
8%5E%282y-1%29=8%5E%282%281%2Flog%282%29%29-1%29=+8%5E5.64385618977472=125000


Answer by ikleyn(52776) About Me  (Show Source):
You can put this solution on YOUR website!
.
If 2^y=10, find the value of 8^(2y-1)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 


8%5E%282y-1%29 = %281%2F8%29%2A8%5E%282y%29 = %281%2F8%29%2A%288%5Ey%29%2A%288%5Ey%29 = 


    now replace in this formula 8%5Ey by 10%5E3  to get


= %281%2F8%29%2A1000%2A1000 = 1000000%2F8 = 125000.    ANSWER

Solved.