ppts.net
当前位置:首页>>关于(1)化简:(-2ab+3a)-2(2a-b)+2ab;(2)化简...的资料>>

(1)化简:(-2ab+3a)-2(2a-b)+2ab;(2)化简...

(1)原式=-2ab+3a-4a+2b+2ab=2b-a;(2)原式=xy- 2 3 y- 2 3 - 1 2 x+ 1 2 xy-1= 3 2 xy- 2 3 y- 1 2 x- 5 3 ,当x= 2 3 ,y= 3 4 时,原式= 3 2 × 2 3 × 3 4 - 2 3 × 3 4 - 1 2 × 2 3 - 5 3 =- 7 4 .

(1)原式=-2ab+3a-4a+2b+2ab=-a+2b;(2)原式=2a 2 -[3a-5a+2+2a 2 ]=2a 2 -3a+5a-2-2a 2 =2a-2.

(1)原式=-2ab+3a-4a+2b+2ab=2b-a;(2)原式=2x2-3x+1-5+3x-x2=x2-4;(3)2(x2y+xy)-3(x2y-xy)-4x2y=2x2y+2xy-3x2y+3xy-4x2y=-5x2y+5xy当x=1,y=-1时,原式=-5×12×(-1)+5×1×(-1)=0.

解: -(3a²-4ab)+[a²-2(2a+2ab)] =-3a²+4ab+a²-4a-4ab =(-3a²+a²)+(4ab-4ab)-4a =-2a²-4a a=-2时, -2a²-4a=-2a(a+2) =-2·(-2)·(-2+2) =0 化简按部就班做就可以了,注意负负得正。本题b=1是多余条件,...

解:(1)原式= = ;(2)原式= x 2 ﹣3x 2 ﹣3xy+ y 2 + x 2 +3xy+ y 2 =y 2 ;(3)原式=3a 2 ﹣6ab﹣3a 2 +2b﹣2ab﹣2b=﹣8ab, 当a=﹣ ,b=﹣3时,原式=﹣8×(﹣ )×(﹣3)=﹣12

(1)16a 2 b﹣9ab 2 ;(2)﹣65。

2(ab²-2a²b)-3(ab²-a²b)+(2ab²-2a²b) =2ab²-4a²b-3ab²+3a²b+2ab²-2a²b =ab²-3a²b 当a=2,b=1时 原式=ab²-3a²b=2-12=-10

(3a2b-2ab+ab2)-(2a2b-2ab2+7ab) =3a2b-2ab+ab2-2a2b+2ab2-7ab =a+2ab4-9ab 当a=1,b=-2时 =1+2×1×(-2)×4-9×1×(-2) =1+(-16)-(-18) =3 不懂可追问!

=-1/3ab(2a^2b-4ab+ab^2) =-2/3a^3b^2+4/3a^2b^2-1/3a^2b^3 =a^2b^2(-2/3a+4/3-1/3b) 把a=-1又1/2 即a=-3/2,b=-2代入原式,得 =(-3/2)^2(-2)^2[(-2/3)*(-3/2)+4/3-1/3*(-2)] =9/4*4[1+4/3+2/3] =27

|a+3b+1|+(2a-4)的二次方=0 ∴a+3b+1=0 2a-4=0 ∴a=2,b=-1 3a的2次方b-[2ab的平方-2(ab-3/2a的二次方b)]+2ab =3a²b-2ab²+2ab-3a²b+2ab =-2ab²+4ab =-2*2*(-1)²+4*2*(-1) =-4-8=-12

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