4x^ 20x 25因式分解-搜答案-拍题作业网

4x²-20x+15=0x²-5x+25/4=10/4(x-5/2)²=10/4x=5/2+√10/2x=5/2-√10/2再问：解等于多少要小数再答：x=4.081x=

4(x+y)^2-20(x+y-1)+5=4(x+y)^2-20(x+y)+20+5=4(x+y)^2-20(x+y)+25=[2(x+y)]^2-2*[2(x+y)]*5+5^2=[2(x+y)-5

因式分解4(x²-1)

=4(x+1)(x-1)

因式分解x^2-4x

x^2-4x=x(x-4)

1-4X平方因式分解.

1-4x²=(1-2x)(1+2x)

xy^2-4x 因式分解

xy^2-4x=x(y+2)(y-2)-2a^2+4ab-2b^2=-(a-b)^2a^2(x-y)+b^2(y-x)=(x-y)(a+b)(a-b)(a^2+b^2)^2-4a^2b^2=(a+b)

1）3.5x0.25+360x0.25+0.25x36.5=0.25x(3.5+360+36.5)=100.2)(7.25x0.4+2.75x0.4）/0.1=0.4x(7.25+2.75)/0.2=

4(x+y)^2+25-20(x+y)=(2x+2y-5)^2再问：过程

原式=4（x^2-5x-14）=4（x-7）（x+2）

20x2+253x+800=(5X+32)(4X+25)(x+y)²=(x+y)²（x+y)²=（x²+y²+2xy）²=(x²+

因式分解4x²-20x-56

4x²-20x-56=4(x²-5x-14)=4(x-7)(x+2)

4（x+y)2+25-20（x+y)=[2(x+y)]²-2×2(x+y)×5+5²=[(2(x+y)-5]²=(2x+2y-5)²

1、（20+4）x25=20x25+4x25=500+100=6002、35x37+65x37=(35+65)x37=100x37=37003、25x41=25x(40+1)=25x40+25x1=1

试验比较小的整数是否是x³-4x+20=0的解,是有理数范围内此式是不可分解的.三个根是-3.201197089,1.600598545-1.919829968I,1.600598545+1

因式分解：x^4-y^4

x^4-y^4=(x²-y²)(x²+y²)=(x-y)(x+y)(x²+y²)

3.14x11/8+0.314x25/4-3.14x.02=3.14x11/8+3.14x2.5/4-3.14x.02=3.14x11/8+3.14x5/8-3.14x.02=3.14x（11/8+5

5X64X25X125X93=5X2×4×8X25X125X93=(5X2)×(4X25)×(8X125)X93=93X10×100×1000=93000000（1-1/3-2/5-1/4）X60=1

解x^4-x^2-20=0(x^2-5)(x^2+4)=0∵x^2+4≠0∴x^2-5=0∴x^2=5∴x=√5或x=-√5