Question

Tính:

(a+b+c)^2=

(a+b-c)^2=

(a-b-c)^2=

Answer 1

(a+b+c)²=a²+b²+c²+2ab+2ac+2bc

(a+b-c)²=a²+b²-c²+2ab-2ac-2bc

(a-b-c)²=a²-b²-c²-2ab+2ac+2bc

Answer 2

( a + b + c )² = a² + b² + c²

( a + b - c )² = a² + b² - c²

( a - b - c )² = a² - b² - c²

Answer 3

a)(a+b+c)2(a+b+c)2

=[(a+b)+c]2[(a+b)+c]2 

=(a+b)2(a+b)2+2.(a+b).c+ c2c2 

=a2a2+2ab+ b2b2+2ac+2bc+ c2c2 

= a2a2+ b2b2+ c2c2+2ab+2bc+2ac 

b)(a+b−c)2(a+b−c)2

=[(a+b)−c]2[(a+b)−c]2

=(a+b)2(a+b)2-2.(a+b).c+ c2c2 

=a2a2+2ab+ b2b2-2ac-2bc+ c2c2

= a2a2+ b2b2+ c2c2+2ab-2bc-2ac 

c)(a−b−c)2(a−b−c)2

=[(a−b)−c]2[(a−b)−c]2

=(a−b)2(a−b)2-2.(a-b).c+ c2c2 

=a2a2-2ab+ b2b2-2ac+2bc+ c2c2

= a2a2+ b2b2+ c2c2-2ab+2bc-2ac