Given a polynomial p(x) = x5−9x4+24x3−52x+48. The zeroes of the polynomial are √2,−√2 and 2. Find the other 2 zeroes.
3 and 4
Given zeroes are √2,−√2 and 2
g(x) = (x−√2)(x+√2)(x−2) =(x2−2)(x−2) = x3−2x2−2x+4
Dividing p(x) by g(x)
x2−7x+12x3−2x2−2x+4x5−9x4+24x3−6x2+52x+48 x5−2x4−2x3+4x2–––––––––––––––––––––––2 −7x4+26x3−10x2+52x −7x4+14x3−14x2−28x––––––––––––––––––––––––––––– 12x3−24x2+24x+48 12x3−24x2−24x+48–––––––––––––––––––––––––– 0
q(x) = x2−7x+12
p(x) = g(x) h(x)
=(x3−2x2−2x+4)(x2−7x+12)
The other two zeroes are in x2−7x+12
=x2−4x−3x+12 = x(x−4)−3(x−4) = (x−3)(x−4)
Hence, the zeroes are 3 and 4