Question

(x+2y-3z)^2怎么样套用公式

Answer 1

把x看做a,2y看做b，-3z看做c，就可以了。
(a+b+c)^2=a^2+b^2+c^2+2ab+2bc+2ca
(x+2y-3z)^2
=[x+(2y)+(-3z)]^2
=x^2+(2y)^2+(-3z)^2+2x(2y)+2(2y)(-3z)+2x(-3z)
=x^2+4y^2+9z^2+4xy-12yz-6xz

Answer 2

[(x+2y)-3z]^2
=(x+2y)^2-2*(x+2y)*3z+9z^2
=x^2+4xy+4y^2-6xz-12yz+9z^2
首先把x+2y看成是一项，然后在将其展开！

Answer 3

(a+b+c)^2=a^2+b^2+c^2+2ab+2bc+2ac
(x+2y-3z)^2=x^2+4y^2+9z^2+4xy-12yz-6xz

Answer 4

(a+b+c)^2=a^2+b^2+c^2+2ab+2bc+2ac
(x+2y-3z)^2
=[(x+2y)-3z]^2
=(x+2y)^2-2*(x+2y)*3z+9z^2
=x^2+4xy+4y^2-6xz-12yz+9z^2