Question

已知：a=二分之一m+1,b=二分之一m+2,c=二分之一m+3,求a的平方+2ab+b的平方-2ac+c的平方-2ac

Answer 1

a+b-c

=1/2m+1+1/2m+2-1/2m-3

=1/2m

a^2+2ab+b^2-2ac+c^2-2bc

=(a+b)^2-2(a+b)c+c^2

=(a+b-c)^2

=(1/2m)^2

=(1/4)m^2