Question

Daca x^2-y^2=60 si 3x-3y=36 aflati x+y
AJUTOR SUNT LA TEST

Answer 1

3x-3y = 3(x-y) = 36
x-y = 36 : 3 = 12

x^2 - y^2 = (x-y)(x+y) = 60
12(x+y) = 60
x+y = 60 : 12
x+y = 5