a+ 1/a = 5a²/a + 1/a = 5(a²+1)/a = 5a²+1 = 5aa²-5a = -1a²-5a+6.25=5.25(a-2.5)²=5.25∴a-2.5=±(√21)/2∴a1=2.5+(√21)/2a2=2.5-(√21)/2