SOLUTION: Solve for x. a.) 7^x+1 + 7^x + 7^x-1 = 399 b.) (4^x+2)(5^x+1) = 32000 c.) (2^x-3)(5^x+1) = 625

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: Solve for x. a.) 7^x+1 + 7^x + 7^x-1 = 399 b.) (4^x+2)(5^x+1) = 32000 c.) (2^x-3)(5^x+1) = 625      Log On


   

Question 942773: Solve for x.
a.) 7^x+1 + 7^x + 7^x-1 = 399
b.) (4^x+2)(5^x+1) = 32000
c.) (2^x-3)(5^x+1) = 625
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Don't forget to use parentheses around the exponents.
,
,
a)7%5E%28x%2B1%29+%2B+7%5Ex+%2B+7%5E%28x-1%29+=+399
49%2A7%5E%28x-1%29%2B7%2A7%5E%28x-1%29%2B7%5E%28x-1%29=399
%2857%297%5E%28x-1%29=399
7%5E%28x-1%29=7
x-1=1
x=2
.
.
b)4%5E%28x%2B2%295%5E%28x%2B1%29=32000
16%2A4%5Ex%2A5%2A5%5Ex=32000
20%5Ex=400
x=2
.
.
c)2%5E%28x-3%295%5E%28x%2B1%29=625
%281%2F2%5E3%29%2A2%5Ex%2A5%2A5%5Ex=625
%281%2F8%29%2A2%5Ex%2A5%2A5%5Ex=625
10%5Ex=1000
x=3