How many significant figures are in the number 0.002849?

Hi my sisters and brothers can tell me the answer because i don’t understand the question

The parabola y = x² - 4 opens: a.) up b.) down c.) right d.) left

Match the equivalent expressions. x - 3y + 12 12 - 3y - 2x + x + 2x 3x + 2y - 2x + y + 12 3y + 12 3x + y - 12 4y + 3y + 3x - 6y - 10 - 2 x + 3y + 2x - 3x + 7 + 5 x + 3y + 12 5 + 2y + 7x - 4x + 3y - 17