Does anyone know this answer? it's like that answer to a problem, Example: 12 + the sum of 9+19=? 12a X 9b=?

a=9
b=6

The valve seat performs two functions: it provides a seal for the valve in the combustion chamber, and it provides a cool surface to carry heat away from the valve. most valves use a seating angle.

4. when a child cries out during rough play, the caregiver should a. encourage the distressed child to fight back. b. respond immediately, since the behavior has changed to fighting. c. ignore it, because rough play is a natural part of children’s learning. d. ignore the request for unless there has been an injury. i need answer

54 points human geography in advance