(х+2)(х^2 +2х+4)-х(х-3)(х+3)=26
X^3+2x^2+4x+2x^2+4x+8-x^3-9x=26 4x^2-x-18=0 D=1+4*18*4=289 x12=(1±17)/8 x1=2.25 x2= -2