I would suggest doubling the angle of 45 degrees so that you can apply the Pythagorean Thereom

great job! I was thinking move the -21 to the other side and say b^2-4ac<0

I agree, just simplify and if the denominator is imaginary or complex, say 10i+10, multiply by 10-10i

where are the 2 sides? I can't see them. If they are x and y, then it is all the integers from (the smallest integer larger than x-y), all the way to (the largest integer smaller than x+y)

b: (ax+b)^6 has a x^4 coefficient of 15*a^4*b^2, so in this case a = 2, b = -5, so 15*16*25 = 3*8*2*125 = 6000

so, basically, say x is the amount of days 1 person can do the task in. then x/5-x/6=8, meaning x=240, and 5 workers take 48 days, so if you want to take 20 days, you have to have 12 workers. 12-5 = 7, so you need 7 extra workers!

simplify to x^2+10x-10 = 0

plug it in the quadratic formula!

So basically is there are x sides, there will be x*(x-1)/2 - x diagonals, and if 2x = x*(x-1)/2 - x, then x must equal to 7, septagon. Go on, try it!