15x^5+17x^4+x^3-x^2=0
X^2(15x^3+17x-1)=0
Since 1/5 is a root:
X^2(15X^3+17X-1)
= X^2(X-1/5)(15X^2+AX+5)
=X^2(15X^2+AX^2-3X^2+5X-A/5X-1
=>A=20
X^2(x-1/5)(15X^2+20X+5)
=5X^2(X-1/5)(X+1)(3X+1)
=0
15x^5+17x^4+x^3-x^2=0
X^2(15x^3+17x-1)=0
Since 1/5 is a root:
X^2(15X^3+17X-1)
= X^2(X-1/5)(15X^2+AX+5)
=X^2(15X^2+AX^2-3X^2+5X-A/5X-1
=>A=20
X^2(x-1/5)(15X^2+20X+5)
=5X^2(X-1/5)(X+1)(3X+1)
=0