#### Answer

{(x,y)|y=3x-5}
infinitely many solutions

#### Work Step by Step

y=3x-5
Plug this value for y into the other equation.
21x-35=7y
21x-35=7(3x-5)
21x-35=7(3x)-7(5)
21x-35=21x-35
21x-21x-35=21x-21x-35
-35=-35
Since this statement is true, there are infinitely many solutions and the solution set contains either of the equations in the system. For example, {(x,y)|y=3x-5}.