(iii) m2 – 3m – 1 = 0
Sol. m2 – 3m – 1 = 0
∴ m2 – 3m = 1 .... (i)
Third term = ( ½ × coefficient of m)2
= ( ½ × - 3)2
= (-3/2)2
= 9/4
Adding 9/4 to both sides of (i), we get,
m2 – 3m + 9/4 = 1+ 9/4 .... (i)
∴ (m – 3/2)2 = 13/4
∴ (m – 3/2) = ± √(13/4)
∴ m – 3/2 = ± √13 /2
∴ m = 3/2 ± √13/2
∴ m = (3±√13)/2
∴ m = (3+√13)/2 or (3 - √13)/2
