Solve x² - 11x + 10 = 0
The solutions of x² - 11x + 10 = 0 are x = 10 or x = 1.
Change a, b or c (whole numbers, a not 0) and the exact solutions follow.
How to work it out
- 1
Write it in standard form a x² + b x + c = 0 and read off the coefficients: a = 1, b = -11, c = 10.
- 2
Work out the discriminant D = b² − 4ac. Its sign tells you how many real solutions there are.
- 3
D is positive, so there are two different real solutions.
- 4
Method 1, factoring. The roots are rational, so the left side factors:
- 5
A product is zero when one of its factors is zero, so set each factor equal to 0 and solve:
- 6
Method 2, The quadratic formula works for every quadratic:
- 7
Simplify to get the solutions:
- 8
Check by putting x = 10 back in: a·x² + b·x + c = 1·(100) + (-11)·(10) + 10 = 0 ✓
LaTeX source of the formulas on this page
\[ x^2 - 11x + 10 = 0\ \Rightarrow\ x = 10,\ 1 \]
\[ x^2 - 11x + 10 = 0 \]
\[ D = (-11)^2 - 4\cdot1\cdot10 = 121 - 40 = 81 \]
\[ \left(x - 10\right)\left(x - 1\right) = 0 \]
\[ x - 10 = 0 \Rightarrow x = 10\qquad x - 1 = 0 \Rightarrow x = 1 \]
\[ x = \frac{-b \pm \sqrt{D}}{2a} = \frac{11 \pm \sqrt{81}}{2} \]
\[ x = 10\quad\text{or}\quad x = 1 \]The parabola y = x² - 11x + 10
| x | y |
|---|---|
| 2.5 | -11.25 |
| 3.5 | -16.25 |
| 4.5 | -19.25 |
| 5.5 | -20.25 |
| 6.5 | -19.25 |
| 7.5 | -16.25 |
| 8.5 | -11.25 |
Questions
What are the solutions of x² - 11x + 10 = 0?
The solutions of x² - 11x + 10 = 0 are x = 10 or x = 1.
Does x² - 11x + 10 = 0 factor?
Yes: (x-10)(x-1) = 0.
What is the vertex of y = x² - 11x + 10?
(11/2, -81/4). The parabola opens upwards, so this is the minimum.
What are the sum and product of the roots?
Sum = −b/a = 11, product = c/a = 10.