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ella [17]
3 years ago
8

Solve for x.....................

Mathematics
2 answers:
Naddika [18.5K]3 years ago
8 0

Answer:

C. x=\frac{7}{3} and x=\frac{-3}{2}

Step-by-step explanation:

We have the quadratic equation 6x^{2}-5x-21=0.

Now, the roots of the quadratic equation ax^{2}+bx+c=0 are given by x=\frac{-b\pm \sqrt{b^{2}-4ac}}{2a}.

So, from the given equation, we have,

a = 6, b = -5, c = -21.

Substituting the values in x=\frac{-b\pm \sqrt{b^{2}-4ac}}{2a}, we get,

x=\frac{5\pm \sqrt{(-5)^{2}-4\times 6\times (-21)}}{2\times 6}

i.e. x=\frac{5\pm \sqrt{25+504}}{12}

i.e. x=\frac{5\pm \sqrt{529}}{12}

i.e. x=\frac{5\pm 23}{12}

i.e. x=\frac{5+23}{12} and i.e. x=\frac{5-23}{12}

i.e. x=\frac{28}{12} and i.e. x=\frac{-18}{12}

i.e. x=\frac{7}{3} and i.e. x=\frac{-3}{2}

Thus, the value for x are \frac{7}{3} and \frac{-3}{2}

Inessa [10]3 years ago
5 0

Answer:

Option C is correct, i.e. x = 7/3, x = -3/2.

Step-by-step explanation:

Given the equation is 6x² -5x + -21 = 0.

Then a = 6, b = -5, c = -21

Using the Quadratic formula, x = ( -b ± √(b² -4ac) )/2a

x = ( +5 ± √((-5)² -4*6*-21) )/2*6

x = ( 5 ± √(25 +504) )/12

x = ( 5 ± √(529) )/12

x = ( 5 ± 23 )/12

x = (5-23)/12 or x = (5+23)/12

x = -18/12 or x = 28/12

x = -3/2 or x = 7/3

Hence, option C is correct, i.e. x = 7/3, x = -3/2.

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