第1个回答 2011-02-20
1.25X48
=1.25*(40+8)
=1.25*40+1.25*8
=50+10
=60;
3.18X3.6+3.18X3.6
=3.18*3.6*2
=3.18*7.2
=3.18*(7+0.2)
=3.18*7+3.18*0.2
=22.26+0.636
=22.896.
7.2*10.1
=7.2*(10+0.1)
=7.2*10+7.2*0.1
=72+0.72
=72.72
解方程:0.7(3+×)=2.8
3+x=2.8/0.7
3+x=4
x=4-3
x=1
5.2x-x=29.4
x(5.2-1)=29.4
x*4.2=29.4
x=29.4/4.2
x=7.
第2个回答 2011-02-24
1 1.25X48
解：原式=1.25×8×6=10×6=60
3.18X3.6+3.18X3.6
解：原式=3.18×3.6×2=22.896
7.2乘10.1
解：原式=7.2×（10+0.1）
=7.2×10+7.2×0.1
=72+0.72
=72.72
解方程:0.7(3+×)=2.8
解：可化为3+x=4
x=1
5.2x-x=29.4
解：可化为4.2x=29.4
x=7
2 1.25X48
=1.25*(40+8)
=1.25*40+1.25*8
=50+10
=60;
3.18X3.6+3.18X3.6
=3.18*3.6*2
=3.18*7.2
=3.18*(7+0.2)
=3.18*7+3.18*0.2
=22.26+0.636
=22.896.
7.2*10.1
=7.2*(10+0.1)
=7.2*10+7.2*0.1
=72+0.72
=72.72
解方程:0.7(3+×)=2.8
3+x=2.8/0.7
3+x=4
x=4-3
x=1
5.2x-x=29.4
x(5.2-1)=29.4
x*4.2=29.4
x=29.4/4.2
x=7.
第3个回答 2012-04-30
1.25X48
=1.25*(40+8)
=1.25*40+1.25*8
=50+10
=60;
3.18X3.6+3.18X3.6
=3.18*3.6*2
=3.18*7.2
=3.18*(7+0.2)
=3.18*7+3.18*0.2
=22.26+0.636
=22.896.
7.2*10.1
=7.2*(10+0.1)
=7.2*10+7.2*0.1
=72+0.72
=72.72
解方程:0.7(3+×)=2.8
3+x=2.8/0.7
3+x=4
x=4-3
x=1
5.2x-x=29.4
x(5.2-1)=29.4
x*4.2=29.4
x=29.4/4.2
x=7.