麻烦问下一个数学题.已知a=根号下5,b=-17分之3,求(a+b)乘(a-b)+(a+b)的平方-2ab的值

问题描述:

麻烦问下一个数学题.已知a=根号下5,b=-17分之3,求(a+b)乘(a-b)+(a+b)的平方-2ab的值

(a+b)(a-b)+(a+b) 2-2ab
=a2-b2+a2+b2+2ab-2ab
=2a2
=10

(a+b)乘(a-b)+(a+b)的平方-2ab
=a²-b²+a²+2ab+b²-2ab
=2a²
=2*5
=10

(a+b)(a-b)+(a+b)^2-2ab
=a^-b^2+a^2+b^2+2ab-2ab
=2a^2
=2*(根号5)^2
=2*5
=10

(a+b)*(a-b)+(a+b)^2-2ab=a^2-b^2+a^2+2ab+b^2-2ab=2a^2=10