x=ap.2 camere si y= ap.cu 4 camere
2x + 4y = 64 camere
[ x + y = 20 ] × 2 ⇒2x + 2y = 40
se scad: 2x + 4y = 64 si 2x +2y = 40 si rezulta⇒(2x - 2x)+(4y - 2y) = 64 - 40 2y=24⇒ y=24:2⇒ y = 12 ap.cu 4 camere
2x + 4×12 = 64⇒2x = 64 - 48⇒2x = 16⇒x=16:2
x = 8 apartamente cu 2 camere