Question

Daca a+b=5 si a-b=7, atunci :

 

a) a^{2} - b^{2} =

 

b) a^{2} + 2ab + b^{2}=

 

c) a^{2}- 2ab +b^{2}=

Answer 1

a)a^2-b^2=(a+b)(a-b)=5*7=35
b)a^2+2ab+b^2=(a+b)^2=5^2=25
c)a^2-2ab+b^2=(a-b)^2=7^2=49