Pls, I need help is anyone really good at french!! PLS

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

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?

Cody started biking to the park traveling 15 mph, after some time the bike got a flat so cody walked the rest of the way, traveling 4 mph. if the total trip to the park took 6 hours and it was 46 miles away, how long did cody travel at each speed? solve using rate times time= distance