Solve -x² = 0
The solution of -x² = 0 is x = 0 (a repeated root).
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 = 0, c = 0.
- 2
Work out the discriminant D = b² − 4ac. Its sign tells you how many real solutions there are.
- 3
D is zero, so there is exactly one solution (a repeated root).
- 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 solution:
- 8
Check by putting x = 0 back in: a·x² + b·x + c = -1·(0) + 0·(0) + 0 = 0 ✓
LaTeX source of the formulas on this page
\[ -x^2 = 0\ \Rightarrow\ x = 0 \]
\[ -x^2 = 0 \]
\[ D = 0^2 - 4\cdot(-1)\cdot0 = 0 + 0 = 0 \]
\[ -\left(x\right)\left(x\right) = 0 \]
\[ x = 0 \Rightarrow x = 0 \]
\[ x = \frac{-b \pm \sqrt{D}}{2a} = \frac{0 \pm \sqrt{0}}{-2} \]
\[ x = 0 \]The parabola y = -x²
| x | y |
|---|---|
| -3 | -9 |
| -2 | -4 |
| -1 | -1 |
| 0 | 0 |
| 1 | -1 |
| 2 | -4 |
| 3 | -9 |
Questions
What are the solutions of -x² = 0?
The solution of -x² = 0 is x = 0 (a repeated root).
Does -x² = 0 factor?
Yes: -1(x)(x) = 0.
What is the vertex of y = -x²?
(0, 0). The parabola opens downwards, so this is the maximum.
What are the sum and product of the roots?
Sum = −b/a = 0, product = c/a = 0.