Question

Пожалуйста помогите!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 1

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

a^2 + b^2 + c^2 = 5^2 - 2*3 = 25 - 6 = 19