急!急!急!Maths功課唔識做!20分

A)
(-2a+b)(b-2a)
=-2ab+b^2+4a^2-2ab
=4a^2-4ab+b^2

B)
(3p-6t)(p-2t)
=3p^2-6pt-6pt+12t^2
=3p^2-12pt+12t^2

C)
-x(x-y+3y^2)
=-x^2+xy-3xy^2

D)
(21x-14y-28z)/-7
=-3x+2y+4z

12)
-38x^5y^5z/19xy^4(x^3y^2)
=-38x^5y^5z/19x^4y^6
=-2xz/y

13)
-3/4x+17=5
-3/4x=-12
-3x=-48
x=16

一會再打另一張給你唷

2007-12-27 14:17:25 補充：
B)8X-4=15X 248X-15X=24 4-7X=-28X=-4C)19-(2-5X)=3X (8-4x)19-2 5x=3x 8-4x17 5x=-x 85x x=8-176x=-9x=-3/2D)x-4/3 1=X/2

2007-12-27 14:17:46 補充：
E)2a-(1-3a)/2=104a-(1-3a)=207a-1=207A-=21A=3f)7-(2X-1)/5=(3X 4)/3 ----*15105-6x 3=15x 20108-20=15x 6x21x=88x=88/21

11a (-2a+b)(b-2a)
= b(-2a+b)-2a(-2a+b)
= -2ab+b*b+4a*a-2ab
= -4ab+b*b+4a*a
11b (3p-6t)(p-2t)
=p(3p-6t)-2t(3p-6t)
=3p*p-6tp-6pt-12t*t
=3p*p12t*t*-12pt
11c -x(x-y+3y*y)
=-x*x+x*y-3x*y*y
=xx+xy-3xyy
11d (21x-14y-28z)/(-7)
= -3x+2y+4z

11b.(3p-6t)(p-2t)
先抽同類項
3(p-2t)(p-2t)
=(p-2t)(3-1)#