10m cubed of air weigh 13 kg. the weight of air is directly proportional to its volume. find the constant of variation; it is called density

k = 1.3

let the weight be w and volume be V, then

since weight is directly proportional to volume

w = kV ← k is the constant of variation, hence

k =

using the given condition, then

k = = 1.3

- 2 + 10x³ - 21x² + 19x - 4

step-by-step explanation:

each term in the second factor is multiplied by each term in the first factor

x²(- 2x² + 4x - 1) - 3x(- 2x² + 4x - 1) + 4(- 2x² + 4x - 1) ← distribute

= - 2 + 4x³ - x² + 6x³ - 12x² + 3x -8x² + 16x - 4

collect like terms

= - 2 + 10x³ - 21x² + 19x - 4 ← in standard form

mark branliest

step-by-step explanation:

.6 is 1/2 of 12

the answer is actually d. i just took the test