20×18 (x-20)×2.5-1.9x=4解方程怎么算-搜答案-神马作文网

（20-2x)(20-2x)x>400400-80x+4x²>400x²-20x＞0x(x-20)＞0x＜0x＞20

1.x+60%x=421.6x=42x=26.252.x-25%x=180.75x=18x=243.3x+20%x=483.2x=48x=1.25纯手打

12=【1】x【3】x【4】18=【1】x【3】x【6】12和18的最大公因数20＝【2】x【2】x【5】30＝【5】x【3】x【2】

6x+1.5x=97.5x=9x=9/7.5X=1.218-0.2X=80.2X=18-8X=10/0.2X=50X-0.25=0.8X=0.8+0.25X=1.05

如图,两个实数解,x=-2.21946和0.0326566这是个20次的方程,基本没法用手算的.

(X-X*20%-18)-（X-X*20%-18）*10%=X*1/2-3则（X*80%-18）*90%=X*1/2-372%*X-16.2=X*1/2-322%*X=13.2X=60

原方程可化为100*{(X+X*20%)-[(1200-X)-(1200-X)*20%]}=40%*100100*120%X-100*[(1200-X)-(1200-X)*20%]=40120X-10

20%x+18%(x+30)=18.8%(x+x+30）（0.2+0.18)x+0.18*30=0.188（2x+30）0.38x+5.4=0.376x+5.640.004x=0.24x=60

2.5%X+20*2.25%-2.25%X=0.4850.25%X+20*2.25%=0.4850.25%X=0.485-20*2.25%0.25%X=0.485-0.450.25%X=0.035X=

x+3/20x=4623x/20=46x=46x20/23=40,x-1/5x=404x/5=40x=200/4=50,x-1/2x=3/4x/2=3/4x=3/2,x-0.2x=180.8x=18x

1、3x²+6x+3=03（x²+x+1)=0即:x²+x+1=0x²+x+1/4+3/4=0(x+1/2)²+3/4=0(x+1/2)²=

(x-22)+(x-24)+(x-27)+(x-20)=xx-22+x-24+x-27+x-20=x4x-93=x4x-x=933x=93x=31

1/√x(√x+2)=1/√x-1/(√x+2)=(√x+2-√x)/√x(√x+2)所以,1/√x(√x+2)+1/(√x+2)(√x+4)+1/(√x+4)(√x+6)+.+1/(√x+18)(√

各分式减1,得1/（x+2004)+1/(x+2006)=1/(x+2007)+1/(x+2003),通分得（2x+4010)/[（x+2004)(x+2006)]=(2x+4010)/[(x+200

0.88（X+20%X)=X+84

0.88x+0.88*20%x=x+841.056x=x+84x=1500

3/4x+18-1=0.23/4x=-16.8x=-22.4

50％x=2再答：x=4再答：1.2x=2.4再答：x=2再答：1.05x=4.2再答：x=4再答：0.5x=0.2再答：x=0.4再答：请采纳再问：可不可以把式子、过程、答案合并在一起再答：那就是过

（1）20%X+30%X=2.5 50%X=2

20/x=20/(x+2.5)+0.4

两边同乘x*(x+0.5)化简的0.4x*x+x-50=0,所以x=10或-12.5

(4x²-20x+18)/(x²-5x+4)≥3(4x²-20x+18)/(x²-5x+4)-3≥0(4x²-20x+18-3x²+15x-