log这题的x要怎麼求?

2025-05-19 12:09:06
推荐回答(1个)
回答1:

对数有意义,√(x+4)>0,x>-4;10-x>0,x<10
-4log2[√(x+4)] +log¼(6)≤1- log4(10-x)
log4(x+4)-log4(6)+log4(10-x)≤1
log4[(x+4)(10-x)/6]≤1
(x+4)(10-x)/6≤4
x²-6x-16≥0
(x+2)(x-8)≥0
x≤-2或x≥8,又-4不等式的解集为(-4,-2]U[8,10)