What two numbers when multiplied gives $-25$ and when added, $-10$? Factors of $25$ are; $1, 5, 25$
$$5 \times 5 = 25$$
$$5 + 5 = 10$$
$$-5 \times 5 = -25$$
$$-5 + 5 = 0$$
How can I solve this?
Thanks

Solve: $$\begin{align}
xy &=-25 \\
x+y &= -10
\end{align}
$$
In particular, substituting $y=-10-x = -(10+x)$ in the first equation, you get $$x^2+10x -25 = 0 $$
which is an equation you should know how to handle. The two solutions are $x=-5+\sqrt{50} = 5(\sqrt{2}-1)$ and $x=-5(\sqrt{2}+1)$, from which you get respectively $y=-5(\sqrt{2}+1)$ and $y=5(\sqrt{2}-1)$.
