(v) 7x + 1 = 6x2
Sol. 7x + 1 = 6x2
∴ 0 = 6x2 – 7x – 1
∴ 6x2 – 7x – 1 = 0
Comparing with ax2 + bx + c = 0 we have a = 6, b = – 7, c = – 1
b2 – 4ac = (– 7)2 – 4 (6) (– 1)
= 49 + 24
= 73
By Formula method,
x
|
=
|
- b ± √(b2 – 4ac)
| ||
2a
| ||||
∴ x
|
=
|
-(-7) ± √73
| ||
2(6)
| ||||
∴ x
|
=
|
7 ± √73
| ||
12
| ||||
∴ x
|
=
|
7 + √73
|
or
|
7 - √73
|
12
|
12
|
