Q25 of 30 Page 36

If one zero of the polynomial (a2 + 9)x2 + 13x + 6a is reciprocal of the other. Find the value of a.

Zeroes of polynomial means for what value of x the equation becomes 0


The polynomial given is quadratic since the degree is 2


Let one zero of polynomial be α


As the other is its reciprocal hence


Compare (a2 + 9)x2 + 13x + 6a with standard form of quadratic equation px2 + qx + r


p = a2 + 9, q = 13 and r = 6a


product of roots of quadratic




r = p


6a = a2 + 9


a2 – 6a + 9 = 0


a2 – 2(3)a + 32 = 0


Using (a – b)2 = a2 – 2ab + b2


(a – 3)2 = 0


a = 3


Hence a = 3


More from this chapter

All 30 →