208*125=(200+8)*125=200*125+125*8=25000+1000=26000
还有木有,亲。
追答有
求未知数X
3.5:(x-3)=0.4:1.6 (x-1)/4+1=(2x+1)/6
解:3.5/(X-3)=0.4/1.6 解:X/4-1/4-X/3-1/6+1=0
3.5/(X-3)=1/4 (3X-4X)/12+7/12=0
X-3=3.5*4 X=7
X=17
(1)25.65-3/4-(17又3/20-0.75) (2)7258×12又7/8+274.2×128.75
解:=25.65-0.75-(17.15-0.75) 解:=7258*12.875+274.2*128.75
=25.65-0.75-17.15+0.75 =7258*12.875+2742*12.875
= 8.5 =12.875*(7258+2742)
=12.875*10000=128750
(3) (4)
解=(1993*1994-1)/1993+(1993-1)(1993+1) 解:=(1-1/2)+(1/2-1/4)+(1/4-1/8)+(1/8-1/16)+(1/16-1/32)+(1/32-1/64)
=(1993*1994-1)/1993+1993*1993-1*1 =1-1/64
=(1993*1994-1)/1993(1+1993)-1 =63/64
=(1993*1994-1)/1993*1994-1)
=1