Find the sum of all solutions to the equation $3x(x+4) = 66$.

the solutions are:

and the sum of solutions is:

-4

Step-by-step explanation:

the expression is:

doing the multiplication

dividing everything by 3:

we use the quadratic formula to find the solutions:

in this case since we have an equation in the form

where

the quadratic formula is:

from this, using the + sign we find the first solution:

and the second solution:

the sum of the solutions is:

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