ppts.net
当前位置:首页>>关于(1)用配方法解方程:2x2-3x-1=0 (2)解...的资料>>

(1)用配方法解方程:2x2-3x-1=0 (2)解...

题目应该是:2x² - 3x - 1 = 0 用配方法解方程 2x² - 3x - 1 = 0 x² - 3x/2 - 1/2 = 0 x² - 3x/2 + (3/4)² =1/2 +(3/4)² x² - 3x/2 + (3/4)² = 17/16 (x -3/4)² = 17 / 16 x -3/4 = ±√17 / 4 x = ...

(1)x2-3x-2=0, x2-3x=2, x2-3x+94=2+94,(x-32)2=174, x-32=±172,x1=32+172=3+172,x2=32-172=3?172; (2)x2=4(2-x),x2+4x=8,x2+4x+4=12,(x+2)2=12,x+2=±2

(1)方程两边同除以2,得x2+32x-12=0,移项,得x2+32x=12,配方,得x2+32x+(34)2=12+(34)2,即(x+34)2=1716,由平方根的意义,得x+34=±174,所以,x1=?3+174,x2=?3?174;(2)将原方程化为一般形式,得3x2+2x-2=0,这里a=3,b=2,c=-2,...

∵2x 2 +3x+1=0∴2x 2 +3x=-12(x 2 + 3 2 x)=-12(x 2 + 3 2 x+ 9 16 )=-1+ 9 8 ∴2(x+ 3 4 ) 2 = 1 8 即2(x+ 3 4 ) 2 - 1 8 =0故选B.

(1)∵x 2 -4x=-1,∴x 2 -4x+4=3,∴(x-2) 2 =3,∴x-2=± 3 ,∴x 1 =2+ 3 ,x 2 =2- 3 ;(2)方程变形得3x 2 +10x+5=0,∵a=3,b=10,c=5,∴b 2 -4ac=10 2 -4×3×5=40,∴x= -10± 40 2×3 ,∴x 1 = -5+ 10 3 ,x 2 = -5- 10 3 ;(3)∵3(x-5) 2 ...

2x²-x-1=0 x²-0.5x=0.5 x-0.5x+0.0625=0.5625 (x-0.25)²=0.5625 x-0.25=±0.75 x=0.25±0.75 x1=-0.5 x2=1

解:(1)原式 ;(2)移项,得2x 2 -3x=-1,二次项系数化为1,得 配方: 由此可得: x 1 =1, 。

(1)将方程(3x-1) 2 =(x+1) 2 移项得,(3x-1) 2 -(x+1) 2 =0,∴(3x-1+x+1)(3x-1-x-1)=0,∴4x(2x-2)=0,∴x(x-1)=0,解得x 1 =0,x 2 =1.(2)∵2x 2 +x- 1 2 =0,可得,a=2,b=1,c= 1 2 ,∴x=- 1 4 ± 5 4 .(3)∵x 2 -4x+1=0...

(1)由原方程,得(2x-3-x)(2x-3+x)=0,即x-3=0,或3x-3=0,解得,x=3或x=1,故原方程的解为:x1=1,x2=3;(2)∵原方程的二次项系数a=3,一次项系数b=5,常数项c=1,∴原方程的根是:x=?b±b2? 4ac2a=?5±136,即x=?5±136;(3)由原方程,得...

(1):1/2x²+3/2x-2=0→1/2x²+3/2x=2→x²+3x=1→x²+3x+(3/2)²=1+(3/2)²=13/4 →(x+3/2)²=13/4→x+3/2=±(√13)/2→x=(-3±(√13))/2 (2):2x²-3x+1=0→2x²-3x=-1→x²-3x/2+(3/4)²=-1/2+(3/4)...

网站首页 | 网站地图
All rights reserved Powered by www.ppts.net
copyright ©right 2010-2021。
内容来自网络,如有侵犯请联系客服。zhit325@qq.com