-6xy(-x+2y-5z) math題

-6xy(-x+2y-5z)

= 6xxy - 12xyy + 30xyz

2010-06-29 17:16:56 補充：
xx = x ^ 2

I can change :

6xxy - 12xyy + 30xyz

= 6y ( x ^ 2 ) - 12x ( y ^ 2 ) + 30xyz

2010-06-29 17:22:38 補充：
But in 2010 , some people write xx = x2

This let them easy to show x ^ 2

but someone maybe think that x2 = 2x

That 's a problem ,

so , we can write : xx = x ^ 2 or xx = x2 ( this " 2 " is upper then the " x " , more right than " x " too . )

2010-06-29 17:22:42 補充：
if you want to write xx = x2 , is OK , but I think it maybe make 2030 's , 2050 ' s , 2070 ' s ... write the wrone one . ( wrong means not better than x ^ 2 )

-6xy(-x+2y-5z)
=-6x^2y-12xy^2+30xyz

xx=x^2
x+x=2x

x^2=x的2次方

-6xy(-x+2y-5z)
6x^2(y)-12xy^2+30x^2(y)(z)

or
-6xy(-x+2y-5z)

Both of the answers are correct!
Because........
(14(m+n)/2)
7(m+n)
or
7m+7n

Simplify -6xy(-x+2y-5z),

then (-6xy)(-x+2y-5z)

= (-6xy)(-x) + (-6xy)(2y) + (-6xy)(-5z)

= 6xyx -12xyy + 30xyz

= 6x^2 -12xy^2 + 30xyz #

It has been simplified already...