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21 votes
21 votes
Solve the equation using the quadratic formula.

10x²-x+9=0
3
2
B) x = ±3
A) X=
c) No Solution
D x=9

User Gracu
by
2.9k points

1 Answer

22 votes
22 votes

Answer: C) No solution

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Step-by-step explanation:

Compare the given equation to the format of:
a\text{x}^2+b\text{x}+c

We have,

  • a = 10
  • b = -1
  • c = 9

Plug those values into the quadratic formula below.


x = (-b\pm√(b^2-4ac))/(2a)\\\\x = (-(-1)\pm√((-1)^2-4(10)(9)))/(2(10))\\\\x = (1\pm√(-359))/(20)\\\\

The discriminant
d = b^2 - 4ac = (-1)^2-4(10)(9) = -359 is negative, so there are no real numbered solutions. The two solutions are complex numbers in the form a+bi where
i = √(-1).

If your teacher has not covered imaginary numbers or complex numbers yet, then the final answer would be "No solution"

Visually, you could use a graphing calculator (or something like Desmos) to plot out the parabola. The parabola
10\text{x}^2-\text{x}+9 never crosses the x axis. This fact visually indicates there are no real solutions.

User Binoy Dalal
by
2.7k points