Mr. Alvarado bought a total of 20 pounds of grass seed at the nursery for $168. He paid $9 per pound for Kentucky blue grass and $6 per pound for Tall Fescue. Which system of equations can be used to find the amount X (in pounds) of Kentucky blue grass and the amounty (in pounds) of Tall Fescue Mr. Alvarado purchased?
X+ y = 168
9x + y = 20
Ox+y = 20
6x + 9y = 168
x+y = 20
9x + y = 168
Ox+y=168
6x + 9y = 20

The deck that kenneth is building is in the shape of a parallelogram abcd the measure of angle c is one third the measure of angle b find the measure of each angle of the deck

Ineed to know the answer right now! !

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)