Justin worked 2 2/3 hours on thursday and 6 3/4 hours on friday. how many hours combined

Describe all the numbers that when rounded to the nearest thousand are 645,000

y=2x−1 5x−4y=1 is (1,1)(1,1) a solution of the system?

The table below shows the approximate masses of a dust particle and a grain of pollen. dust particle 0.000000778 g grain of pollen 0.00000000155 g the mass of a dust particle can be estimated and written in the form a × 10^b, where a = 8 and b = the mass of a grain of pollen can be estimated and written in the form a × 10^b, where a = 2 and b = based on the estimates, the mass of a dust particle is approximately blank times larger than the mass of a grain of pollen.