What is 4+6÷2÷3? i really need to get this right.

In the past, professional baseball was played at the astrodome in houston, texas. the astrodome has a maximum height of 63.4 m. the height of a baseball t seconds after it is hit straight up in the air with a velocity of 45 ft/s is given by h = -9.8t2 + 45t + 1. will a baseball hit straight up with this velocity hit the roof of the astrodome? use the discriminant to explain your answer.

Twelve less than a number is at most 20

Which of the following values have 3 significant figures? check all that apply. a. 10.1 b. 100.05 c. 120 d. 129