What is the simplification of the expression-4x^2(6x-5x^2-5)

  20x^4 -24x^3 +20x^2

Step-by-step explanation:

Usually, "simplification" means the parentheses are removed, like terms are combined, and terms are written in order of decreasing degree.

-4x^2(6x-5x^2-5)

  = (-4x^2)(6x) +(-4x^2)(-5x^2) +(-4x^2)(-5) . . . . use the distributive property

  = -24x^3 +20x^4 +20x^2

  = 20x^4 -24x^3 +20x^2

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