Express:bear-x;bus-y, cap-z.Equation: 3x+3z=21 ; 3x +2y +z =19; 2x +y +2z = 15.From the 1st equation: 3x + 3z =21 , x+z = 7. From the 2nd of ur-tion: 3x + 2y +z = 19. Otherwise:2x + 2y +x +z = 19 . x + y = 6. From the 3rd :2x + y +2z = 15 ; Otherwise: (x +z) + (x + y) +z =15 ,7 +6 + z =15 , z=2. Substitute in the last ur-tion: x + 2y * z = ?. x =7 - 2 =5,y=6 -5=1. It turns out: 5 + 2 *2 = 9. Something like that.