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17 votes
17 votes
Solve: x^2 - 14x + 58 = 0

User Junichiro
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1 Answer

9 votes
9 votes

We can use the quadratic formula to solve this equation:


x=(-b)/(2a)+/-\frac{\sqrt[]{b^2-4ac}}{2a}

Then, we have:

a = 1

b = -14

c = 58

Thus


x=(-(-14))/(2\cdot1)+\frac{\sqrt[]{(-14)^2-4(1)(58)}}{2\cdot1}\Rightarrow x=(14)/(2)+\frac{\sqrt[]{196-232}}{2}

As we can see, the result will be a complex number solution:


x=7+\frac{\sqrt[]{-36}}{2}\Rightarrow x=7+\frac{\sqrt[]{36i^2}}{2}\Rightarrow x=7+\frac{\sqrt[]{36}}{2}i\Rightarrow x=7+(6)/(2)i\Rightarrow x=7+3i

We have to remember that:


i^2=-1

Then, one of the solution is x = 7 + 3i. Therefore, according to the quadratic formula, the other solution is x = 7 - 3i.

The solutions are x = 7 + 3i and x = 7 - 3i.

User Glinda
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3.7k points