log2 (x + 3) + log2(x + 2) = 1log2 (x + 3) + log2(x + 2) = 1
问题描述:
log2 (x + 3) + log2(x + 2) = 1
log2 (x + 3) + log2(x + 2) = 1
答
log2 (x + 3) (x + 2) =1
(x + 3) (x + 2) = 2
相信后面的步骤难不住你了
答
log2 (x + 3) + log2(x + 2) = 1
log2{(x+3)*(x+2)}=1
(x+3)*(x+2)=2
x^2+5x+4=0
(x+4)(x+1)=0
所以x=-4或-1
因为x+3>0 x+2>0
所以x>-2
所以x=-1