( 1g5 )^2+21g2-( 1g2)^2计算此题.

(1g5)+21g2-(1g2) lg5+lg2*1g5+(1g2)^2 (1g5)的2平方+21g2-(1g2)的2平方 ( 1g5 )^2+21g2-( 1g2)^2计算此题. 1g2+1g5= 1g2+1g5等于 计算(1g5)2+1g2*1g50=多少? 计算2sin180°-1g5-1g2?有急用 1g5-1g2份之一 计算 1g5+1g2等于多少. 化简求值 (1g2)^3+(1g5)^3+3*1g2*1g5 (1g2)^3+(1g5)^3+31g2*1g5=? 1g5^2+1g8^(2/3)+1g5·1g20+(1g2)^2= (1g2)的二次方+1g20乘以1g5 对数计算（1g2）²+1g5·lg20 1g500+1g8/5-1/21g64+50(1g2+1g5)的平方 1g25+2/3g8+1g5乘1g20+(1g2)的平方 解(1g2)^3+(1g5)^3+1g5*1g8