What is the equation of the line –3x–2y=30 in slope-intercept form?

Iam trying to solve a linear equation for the shoe size of someone 84" tall taking into consideration example 1 is 69" tall with a shoe size of 9 and example 2 is 72 inches tall with a shoe size of 11. i understand that the equation should be y=mx+b and that on the graph the answer is (3,2) but i just don't understand how to create the equation to solve for 84-inches and 60-inches tall questions. after two days, i need .

One x-intercept for a parabola is at the point (1,0). use the factor method to find x-intercept for the parabola defined by the equation y=-3x^2+5x+2

Caleb and emily are standing 100 yards from each other. caleb looks up at a 45° angle to see a hot air balloon. emily looks up at a 60° angle to see the same hot air balloon. approximately how far is the hot air balloon off the ground? a)44.2 yd. b)63.4 yd. c)73.2 yd. d)89.7 yd.