log2 56-log2 7怎么算来着?

log2 56-log2 7怎么算来着? 求值：log2 (5/56)^(1/2)+log2 (14)-(1/2)log2 (35)=log2中2为底数=1/2[-2log2 (7)-3]+log2 (2)+log2 (7) 中的1/2[-2log2 (7)-3]是怎么得到的？ log2(6)怎么算 log2^x怎么算 log2 4+log2 (x+2)怎么算?log2 4+log2 (x+2)=log2 (4x+8) [log2(3)]^2怎么算? log2加log5怎么算? log2*1/25怎么算 4^log2^5怎么算 log2根号2怎么算? 4^log2^5怎么算? log2(log2 log2（80）为什么等于7怎么算的 log2(3)×log2(4)=log2(7)?log2(3)×log2(4)=log2(7)吗?log2(1/49)+log2(1/16)+log2(1/27)等于多少呢?帮个忙! 2^log2^8/3怎么算 log2^3*log3^4怎么算 怎么算log2 9乘log3 2 log2为底3怎么算