(xii) 4x2 + 7x + 2 = 0
Sol. 4x2 + 7x + 2 = 0
Comparing with ax2 + bx + c = 0 we have a = 4, b = 7, c = 2
b2 – 4ac = (7)2 – 4 (4) (2)
= 49 – 32
= 17
By Formula method,
x
|
=
|
- b ± √(b2 – 4ac)
| ||
2a
| ||||
∴ x
|
=
|
-(7) ± √17
| ||
2(4)
| ||||
∴ x
|
=
|
-7 ±√17
| ||
8
| ||||
∴ x
|
=
|
-7 + √17
|
or
|
-7 - √17
|
8
|
8
| |||
