( x - 4 )( x - 5 ) - x( x - 6 ) = 10
x^2 - 5x - 4x + 20 - x^2 + 6x = 10
- 9x + 20 + 6x = 10
- 3x = - 10
x = 10/3
x = 3 1/3
D=1+528=529
x1=(-1-23)/12=-2
x2=(-1+23)/12=22/12=11/6
6x^2+1-22=6*(x+2)(x-11/6)=(x+2)(x-11)
S=13²*sin150=169*sin30=169*1/2=84,5