x+(a+17)x+(38-a)x-56=0 x+ax+17x+38x-ax-56=0(ax-ax) + (x-x) +(x+17x-18x) +(18x+38x-56)=0ax*(x-1)+x(x-1)+18x(x-1)+56(x-1)=0(x-1)*(x+ax+18x+56)=0所以:x1=1x2+x3=-a-18x2x3=56当:x2=1时,X3=56,a=-75当:x2=-1时,X3=-56,a=39当:x2=7时,X3=8,a=-33当:x2=-7时,X3=-8,a=-3当:x2=2时,X3=28,a=-48当:x2=-2时,X3=-28,a=12当:x2=4时,X3=14,a=-36当:x2=-4时,X3=-14,a=0a是正整数所以:a的值及方程的整数根如下:a=39 X=(1,-1,-56)a=12 X=(1,-2,-28)