I need help with 9-12 Please show your work

Step-by-step explanation:

well it is because that 9 can't subtract 12, so that's why you take negative twelve plus positive 9

negative twelve comes from the minus twelve and also the positive 9

so that's why negative 3is the answer

since the airplane is moving with constant speed then the distance travelled can be calculated by x=u*t

in km/h would be:

x=640*3.5=2.240 km

in m/s would be:

u=640 km/h= 640.000 m/h =640.000/ 3600 m/s =177.8 m/s

t= 3.5 h= 3.5 * 3600 s=12.600 s

then x=u*t= 177.8*12.600= 2.240.280 m

5050

hope this !