Question

log2(x+4)+log2(x+1)=1+log2 5

Answer 1

log2 (x+4) + log2 (x+1)=1+log2 5,        (x bolše čem -1)
log2 (x+4) + log2 (x+1) = log2 2 +log2 5
log2 (x+4)(x+1) = log2 (2.5)
(x+4)(x+1)=10
x²+5x+4=10
x²+5x-6=0
(x+6)(x-1)=0
a)x+6=0, x=-6 net rešeniem!
b)x-1=0, x=1
Otvet: x=1
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