0.75:x=3:1.2

1)-x=1-2/3x-1/3x=1x=-32)-2x-1.2=4.8-5x3x=6x=23)x=14)x+3=1.5-2x3x=-1.5x=-0.5

3x-18=13.23x=13.2+18x=10.41.5x-x=60.5x=6x=6/0.5=124x+1.2x=265.2x=26x=5

(1)0.25x=-5x=-20(2)3x-4x=1-5x=4(3)3x-4x=18-5x=-13(4)1+7=x+7xx=1(5)9x-7x-3x=-8x=8(6)-x+3x=3-2x=1/2(7)

是这样的：x^5+x^4=x^3(x^2+x)=(x^2+x)[(x^3-1)+1]=(x^2+x)(x^3-1)+x^2+x=[x(x+1)(x-1)](x^2+x+1)+x^2+x=(x^3-x)

x-(1.25-x)=1.2x-1.25+x=1.2x+x=1.2+1.252x=2.45x=1.2253x-(1+x)=1.83x-1-x=1.83x-x=1.8+12x=2.8x=1.4

1.2x²-4x=1x²-2x-1/2=0x²-2x+1-1-1/2=0（x-1）²=3/2x-1=±√6/2x1=1+√6/2x2=1-√6/22.x&sup

x(1+2+...+9)=x(9-8-7-...-1)x=0记得采纳啊

1.2x/2x-1+x/x-2=22x(x-2)+x(2x-1)=2(2x-1)(x-2)2x²-4x+2x²-x=4x²-10x+45x=4x=4/5检验：x=4/5是

3.2+x=4.6x=4.6-3.2x=1.4x-2.08=5.76x=5.76+2.08x=7.841.2x=0.84x=0.84÷1.2x=0.73x+0.5x=4.23.5x=4.2x=4.2÷

x+20％x=3601.2x=360x=300x+50％x=0.751.5x=0.75x=0.53分之一x-4分之一x=24分之一1/12x=1/24x=1/2x-35％x=3900.65x=390x

1.2x+0.3x=241.5x=24x=24/1.5x=168x-3x=21.055x=21.05x=21.05/5x=4.21

解(1)x-0.75x=120.25x=121/4x=12x=12×4x=48(2)2.8x+x=7.63.8x=7.6x=7.6÷3.8x=2(3)2.36x+2.64x=185x=18x=18÷5

3-0.2=1.2X-0.8X2.8=0.4XX=7

设x1=4-√3,x2=4+√3,是方程X^2-8X+13=0的两根所以X1^2-8X1+15=2X^4-6X^3-2X^2+18X+23=(X+1)^2*(X^2-8X+13)+10=10所以原式=

1、2x-4–12x+3=9-9x-10x-1=9-9xx=-102、9x+64=100-9x18x=36x=23、15-8+5x=7x+4-3x7+5x=4x+4x=-34、3x-21-2(9-8+

应该是-2x²,不是-3x²3x²-x=1原式=9x^4-3x³+15x³-5x²+3x²-7x+2001=3x²(3x

3x+0.5x=4.23.5x=4.2x=4.2÷3.5x=1.24x-2.16=1.24x=3.36x=0.84x-0.2x=160.8x=16x=202x-4x乘以2.5=3.62x-10=3.6

1.2x²-4x-1=0x²-2x-1/2=0x²-2x+1-1-1/2=0（x-1）²-3/2=0x-1=±√（3/2）x1=1+√6/2x2=1-√6/22

#includesintjiesheng(intn)//用于计算阶乘如：3!{if(n=1)rerunn;returnn*hh(n-1)}doubledigui(intn,intx)//用以计算y=x

①5x-3=3x-1+2-2x5x+3=x+14x=-2x=-1/2②3x-1+2-2x=1.2-2.7xx+1=1.2-2.7x3.7x=0.2x=0.054054③5x-3=1.2-2.7x7.7