(2x+1)^2-(3x-5)^2=-24 4x^2+4x+1-(9x^2+25-30x)=-24 4x^2-9x^2+4x+30x+1-25+24=0 -5x^2+34x=0 x(34-5x)=0 x1=0 или x2=6.8 0+6.8=6.8