Question

x-y=9
x+y=11
Determine if the solution is one, none, or infinitely many. If it's one then name the solution.

Answer 1

This is a set of paralell equations. You would use substitution for this.

Solve for x on the first equation.

x-y=9
Add y to both sides
x=y+9

Now plug in y+9 for each x in the second equation.

y+9+y=11
Combine like terms
2y+9=11
Subtract 9
2y=2
Divide by 2
y=1

Now go back to the first equation and plug in 1 for y.

x-1=9
Add 1
x=10

You now know that x=10 and y=1. One solution.

Hope this helped! :D

Answer 2

Thank you! :)

Answer 3

Thats what openstudy is for :)