Discriminant is b^2 -4ac. So it’s (10)^2 - 4 (-4)(-8) = 100 + 128 = 228. When the discriminant is greater than 0 and not a perfect square you have 2 real irrational roots.
The answer is m∠K=70º, m∠M=70º, and m∠L=40º.
The greatest common factor for 12 and 42 is 6
The angle sum of triangle is 180 degrees. 180-37-79
so the ans should be 64 I think