Answer:
An infinite amount
Step-by-step explanation:
The domain and range of the equation [tex]x+y=10[/tex] are both [tex](-\infty, \infty)[/tex] or all real numbers ([tex]\mathbb{R}[/tex]). This means the equation takes on any real value for [tex]x[/tex] and [tex]y[/tex]. Therefore, there are an infinite number of real solutions to the equation.
Conceptually this makes sense. For any number we plug in for [tex]x[/tex], we can change [tex]y[/tex] to make [tex]x+y=10[/tex] true. Since there are an infinite number of numbers, there are an infinite number of values we can plug in for [tex]x[/tex] and [tex]y[/tex].