Question

已知m-n=-2,n-p=3,求m的平方加n的平方加p的平方减mn减mp减np

Answer 1

n=p+3

m=p+1

所以m^2+n^2+p^2-mn-mp-np

=1/2[(m-n)^2+(m-p)^2+(n-p)^2]

=1/2(2^2+3^2+1^2)

=1/2(4+9+1)

=7

欢迎提问