X + 2y = 10 . . . (1)
6y = -3x + 30 . . . (2)
From (2), 3x + 6y = 30
3(x + 2y = 10)
3 x (1)
Since, the second equation is a multiple of the first equation, the system will have an infinitely number of solutions.


etc.

Hard to select the correct answers without seeing the choices. Let's check a couple,



1.613 jus use a calculator
Let the supplement be s.
180=s+115 => s=180-115= 65 degrees