Question

Solve 3x2 – 18x + 5 = 47 for x.

Answer 1

x = 3 (+-)√23

ANSWER A

Explanation:

Answer 2

x = 3 +√23 and x = 3 - √23

Explanation:

The given equation 3x^2 -18x +5 = 47

This can be written as 3x^2 -18x + 5 - 47 =0

3x^2 -18x - 42 = 0

Here we have to use the quadratic formula.

x =
`(-b +/- √(b^2 - 4ac) )/(2a)`

From the given equation, a = 3, b = -18 and c = -42

Plug in these values in the above formula, we get

x =
`(-(-18) +/- √((-18)^2 - 4.3.(-42)) )/(2.3)`

x =
`(18 +/- √(828) )/(6)`

Simplifying the above expression, we get

x = 3 +√23 and x = 3 - √23

Hope this will helpful.

Thank you.