1. Let's start by stating the problem: solving quadratic simultaneous equations means finding values of variables that satisfy two equations, where at least one is quadratic.
2. A common form is:
$$\begin{cases} ax^2 + bx + c = 0 \\ dx + ey + f = 0 \end{cases}$$
3. Important rules:
- Quadratic equations involve terms like $x^2$.
- Simultaneous means both equations must be true at the same time.
4. To solve, use substitution or elimination:
- Solve one equation for one variable.
- Substitute into the other equation.
5. Example:
$$\begin{cases} x^2 + y = 7 \\ x + y = 3 \end{cases}$$
6. From the second equation, express $y$:
$$y = 3 - x$$
7. Substitute into the first:
$$x^2 + (3 - x) = 7$$
8. Simplify:
$$x^2 - x + 3 = 7$$
9. Move all terms to one side:
$$x^2 - x + 3 - 7 = 0$$
$$x^2 - x - 4 = 0$$
10. Solve quadratic using the formula:
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
where $a=1$, $b=-1$, $c=-4$.
11. Calculate discriminant:
$$\Delta = (-1)^2 - 4 \times 1 \times (-4) = 1 + 16 = 17$$
12. Find roots:
$$x = \frac{1 \pm \sqrt{17}}{2}$$
13. Find corresponding $y$ values:
$$y = 3 - x$$
14. So solutions are:
$$\left( \frac{1 + \sqrt{17}}{2}, 3 - \frac{1 + \sqrt{17}}{2} \right) \text{ and } \left( \frac{1 - \sqrt{17}}{2}, 3 - \frac{1 - \sqrt{17}}{2} \right)$$
This method works for any quadratic simultaneous equations by substitution and solving the resulting quadratic.
Quadratic Simultaneous B83B70
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