Question

Solve for x in the equation 3x^2-18x+5=47

Answer 1

Answer:

x=3±√23

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Step-by-step explanation:

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Answer 2

Answer:

Option 1

Step-by-step explanation:

$3 {x}^{2} - 18x + 5 = 47$

$= > 3 {x}^{2} - 18x + 5 - 47 = 0$

$= > 3 {x}^{2} - 18x - 42 = 0$

$= > 3( {x}^{2} - 6x - 14) = 0$

$= > {x}^{2} - 6x - 14 = 0$

We know that

$x = \frac{ - b + \sqrt{d} }{2a} \: or \: \frac{ - b - \sqrt{d} }{2a}$

Where D = Discriminant of the eqn.

Discriminant of the above eqn.=

${b}^{2} - 4ac = {( - 6)}^{2} - 4 \times ( - 14) \times 1 = 92$

So,

$x = \frac{ - ( - 6) + \sqrt{92} }{2 \times 1} \: or \: \frac{ - ( - 6) - \sqrt{92} }{2 \times 1}$

$= > x = \frac{6 + 2 \sqrt{23} }{2} \: or \: \frac{6 - 2 \sqrt{23} }{2}$

$= > x = (3 + \sqrt{23} ) \: or \: (3 - \sqrt{23} )$