(Q2)find the roots of 4x2 + 3x + 5 = 0 by method of completing the square.
Answer:
Given: 4x2 + 3x + 5 = 0
x2 +
3
4
x +
5
4
= 0
x2 +
3
4
x =
-5
4
x2 +
3
4
x + (
3
8
)2 =
-5
4
+ (
3
8
)2
(x + )2 =
-5
4
+
64
(x + )2 =
-
64
< 0
But (x + )2 cannot be negative for any real value of x.(Why?) So, there is no real value of x satisfying the given equation.
therefore, the given equation has no real roots.