Solve 3x² - 3x = 0
The solutions of 3x² - 3x = 0 are x = 1 or x = 0.
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 = 3, b = -3, c = 0.
- 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 = 1 back in: a·x² + b·x + c = 3·(1) + (-3)·(1) + 0 = 0 ✓
LaTeX source of the formulas on this page
\[ 3x^2 - 3x = 0\ \Rightarrow\ x = 1,\ 0 \]
\[ 3x^2 - 3x = 0 \]
\[ D = (-3)^2 - 4\cdot3\cdot0 = 9 + 0 = 9 \]
\[ 3\left(x - 1\right)\left(x\right) = 0 \]
\[ x - 1 = 0 \Rightarrow x = 1\qquad x = 0 \Rightarrow x = 0 \]
\[ x = \frac{-b \pm \sqrt{D}}{2a} = \frac{3 \pm \sqrt{9}}{6} \]
\[ x = 1\quad\text{or}\quad x = 0 \]The parabola y = 3x² - 3x
| x | y |
|---|---|
| -2.5 | 26.25 |
| -1.5 | 11.25 |
| -0.5 | 2.25 |
| 0.5 | -0.75 |
| 1.5 | 2.25 |
| 2.5 | 11.25 |
| 3.5 | 26.25 |
Questions
What are the solutions of 3x² - 3x = 0?
The solutions of 3x² - 3x = 0 are x = 1 or x = 0.
Does 3x² - 3x = 0 factor?
Yes: 3(x-1)(x) = 0.
What is the vertex of y = 3x² - 3x?
(1/2, -3/4). The parabola opens upwards, so this is the minimum.
What are the sum and product of the roots?
Sum = −b/a = 1, product = c/a = 0.