Question

完全平方公式！！求解！！

（1/3p-5mn)@

(-3a-2b)@

(x+y-z)@

(-3a+1/3b)@

[(a-b)@-(a+b)@]@

我计算非常差，用公式也做不出来。。
过程写详细点，谢谢

@表示平方。1/3是3分之1

Answer 1

（1/3p-5mn)@=(1/3p)@-2*1/3p*5mn+(5mn)@= 1/9p@-10/3pmn+25m@n@

(-3a-2b)@=(-3a)@+2*(-3a)*(-2b)+(-2b)@= 9a@+12ab+4b@

(x+y-z)@=[(x+y)@-2z*(x+y)+z@]@= z@-2xz-2yz+2xy+x@+y@

(-3a+1/3b)@=(-3a)@-2*(-3a)*(1/3b)+(1/3b)@= 9a@-2a+1/9b@

[(a-b)@-(a+b)@]@=[(a-b+a+b)(a-b-a-b)]@= 16a@b@

Answer 2

（1/3p-5mn)@=1/9p^2+5mnp+25m^2p^2

(-3a-2b)@=9a^2+12ab+4b^2

(x+y-z)@=(x+y)^2+z^2-2z(x+y)=x^2+y^2+z^2+2xy-2xz-2yz

[(a-b)@-(a+b)@]@=(-4ab)^2=16a^2b^2

(-3a+1/3b)@=9a^1-2ab+1/9*b^2