SOLUTION: find the value of x log2x+log2(x-3)=2 thanks for the help Lee Ann

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Question 29760: find the value of x
log2x+log2(x-3)=2
thanks for the help
Lee Ann
Answer by Cintchr(481) About Me  (Show Source):
You can put this solution on YOUR website!
logb n = p or b^p = n
b is the base
p is the power
n is the answer
when adding logs of the same base ... you are really multiplying.
log2x + log2(x-3)=2
log2 x(x-3) =2
transform this into the b^p = n form
2%5E2+=+x%28x-3%29 square 2 and distribute the x to (x-3)
4+=+x%5E2+-+3x subtract 4 from both sides
0+=+x%5E2+-+3x+-+4 factor
0+=+%28x-4%29%28x%2B1%29 set each quantity equal to zero
0=x-4 or 0=x+1
x=4 -1=x