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Solve x² - 10x - 6 = 0

The solutions of x² - 10x - 6 = 0 are x = 5 + √31 or x = 5 - √31, that is x ≈ 10.567764 and x ≈ -0.56776436.

x² +x += 0
x2−10x−6=0⇒x=5+31, 5−31x^2 - 10x - 6 = 0 \Rightarrow x = 5 + \sqrt{31},\ 5 - \sqrt{31}
Discriminant D = 124 · x ≈ 10.5678, -0.567764

Change a, b or c (whole numbers, a not 0) and the exact solutions follow.

Graph of y = x² - 10x - 6-224681012-30-20-10102030x = 10.567764x = -0.56776436vertexy = x² - 10x - 6
Graph of y = x² - 10x - 6. The curve crosses the x-axis at x = 10.567764 and x = -0.56776436; the vertex is at (5, -31).

How to work it out

  1. 1

    Write it in standard form a x² + b x + c = 0 and read off the coefficients: a = 1, b = -10, c = -6.

    x2−10x−6=0x^2 - 10x - 6 = 0
  2. 2

    Work out the discriminant D = b² − 4ac. Its sign tells you how many real solutions there are.

    D=(−10)2−4⋅1⋅(−6)=100+24=124D = (-10)^2 - 4\cdot1\cdot(-6) = 100 + 24 = 124
  3. 3

    D is positive, so there are two different real solutions.

  4. 4

    The quadratic formula works for every quadratic:

    x=−b±D2a=10±1242x = \frac{-b \pm \sqrt{D}}{2a} = \frac{10 \pm \sqrt{124}}{2}
  5. 5

    Simplify (pull the square out of the root) to get the solutions:

    x=5+31orx=5−31x = 5 + \sqrt{31}\quad\text{or}\quad x = 5 - \sqrt{31}
  6. 6

    As decimals: x ≈ 10.567764 and x ≈ -0.56776436.

  7. 7

    Check numerically: for x ≈ 10.567764 the left side is 1.4210855e-14 (zero up to rounding) ✓

LaTeX source of the formulas on this page
\[ x^2 - 10x - 6 = 0\ \Rightarrow\ x = 5 + \sqrt{31},\ 5 - \sqrt{31} \]
\[ x^2 - 10x - 6 = 0 \]
\[ D = (-10)^2 - 4\cdot1\cdot(-6) = 100 + 24 = 124 \]
\[ x = \frac{-b \pm \sqrt{D}}{2a} = \frac{10 \pm \sqrt{124}}{2} \]
\[ x = 5 + \sqrt{31}\quad\text{or}\quad x = 5 - \sqrt{31} \]

The parabola y = x² - 10x - 6

xy
2-22
3-27
4-30
5-31
6-30
7-27
8-22

Questions

What are the solutions of x² - 10x - 6 = 0?

The solutions of x² - 10x - 6 = 0 are x = 5 + √31 or x = 5 - √31, that is x ≈ 10.567764 and x ≈ -0.56776436.

Does x² - 10x - 6 = 0 factor?

Not over the integers, because the discriminant 124 is not a perfect square. Use the quadratic formula.

What is the vertex of y = x² - 10x - 6?

(5, -31). The parabola opens upwards, so this is the minimum.

What are the sum and product of the roots?

Sum = −b/a = 10, product = c/a = -6.

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    Solve x² - 10x - 6 = 0: x = 5 + √31 or x = 5 - √31 (steps) | WordGPT