x/=8 x/=-8 55(8+x)-55(8-x)=6(8-x)(8+x) 440+55x-440+55x=6(64-x^2) 6x^2+110x-384=0 3x^2+55x-192=0 D=3025+2304=5329=73^2 x1=(-55-73)/6=-21 1/3 x2=3