Question

X+y=-7 xy=-18 СИСТЕМА

Answer 1

Ответ:

Решение дано во вложении)

Answer 2

To solve the system of equations $x + y = -7$ and $xy = -18$, you can use substitution or elimination. Let's use substitution in this case.

1. Start with the system of equations:

   $$\begin{align*} x + y &= -7 \\ xy &= -18 \end{align*}$$

2. Solve one of the equations for one variable and substitute it into the other equation. Let's solve the first equation for $x$:

   $$x = -7 - y$$

3. Substitute $x = -7 - y$ into the second equation:

   $$(-7 - y)y = -18$$

4. Simplify and solve for $y$:

   $$-7y - y^2 = -18$$

   Rearrange the equation:

   $$y^2 + 7y - 18 = 0$$

   Factor the quadratic equation:

   $$(y + 9)(y - 2) = 0$$

   Set each factor equal to zero and solve for $y$:

   $$y + 9 = 0 \quad \text{or} \quad y - 2 = 0$$

   So, $y = -9$ or $y = 2$.

5. Now that you have the values for $y$, substitute them back into the equation $x + y = -7$ to find the corresponding values for $x$:

   • If $y = -9$, then $x = -7 - (-9) = 2$.
   • If $y = 2$, then $x = -7 - 2 = -9$.

Therefore, the solution to the system of equations is $x = 2, y = -9$ or $x = -9, y = 2$.