Question

СРОЧНО!!!
Розв'яжіть будь-ласка

Answer 1

(a+3c)*(a+b) = a^2+3ca+ab+3cb
ca = 0, т.к. a_|_c.
ab = 0, т.к. a_|_b.

a^2= |a|^2 = 2^2 = 4
bc = |b| |c|*cos45 = 2*2*sqrt(2)/2 = 2sqrt(2)

(a+3c)*(a+b) = a^2+3bc = 4 + 6sqrt(2)