Question

Solve the following equation for x and give, in the following case, your answer correct to 3 decimal places:

3x² – 12x – 1 = 0

Answer 1

3x² – 12x – 1 = 0

Here a = 3, b = –12 and c = –1

∴ `x = (-b +- sqrt(b^2 - 4ac))/(2a)`

`= (-(-12) +- sqrt((-12)^2 - 4(3)(-1)))/(2(3))`

`= (12 +- sqrt156)/6`

= `(12 +- 12.489)/6`

= `(12 + 12.489)/6` and `(12 - 12.489)/6`

= 4.082 and – 0.082