如果a=k+1,b=k+3,c=4-2k,求(a^2+b^2+2ab)+(2ac+2bc)+c^2的值

问题描述:

如果a=k+1,b=k+3,c=4-2k,求(a^2+b^2+2ab)+(2ac+2bc)+c^2的值

(a^2+b^2+2ab)+(2ac+2bc)+c^2
=(a+b+c)^2
=(k+1+k+3+4-2k)
=8^2
=64

(a^2+b^2+2ab)+(2ac+2bc)+c^2
=(a+b+c)^2
=8^2=64

(a^2+b^2+2ab)+(2ac+2bc)+c^2=(a+b)^2+c(2a+2b+c)
=(k+1+k+3)^2+(4-2k)[2(k+1)+2(k+3)+(4-2k)]
=(2k+4)^2+(4-2k)(12+2k)
=64