The answer is the first two inequalities ........
It is 9 because you have a 30,60,90 triangle, and then you can use pythagorean theorem.
3x^2 - 7x + 12 = 0 ....subtract 12 from both sides
3x^2 - 7x = -12 ....divide both sides by 3 to get x^2 by itself
x^2 - 7/3x = -4
His work is not accurate because he divided the second term by 4 instead of 3.
C=1 because you are flipping it over the line so it cant be negative
Put in slope intercept form so the first equation would be y=-x-9 then the second one will be y=-5/2x-16
