Multiply the top equation by 6 and the bottom equation by 7. You will cancel x first by doing this and solve for y. You should get y=-1.
Substitute in y for either original equation.
You should get x=1.
Solution is (1,-1).
30:6 is an equivalent ratio. Anymore and you would have a decimal.
Based off of what I can see in the photo (its too blurry to know for sure) and what I think you're asking:
The angle of a triangle always adds up to 360degrees, so base it on that and the acute and obtuse angles and get the degrees from there, the angle would be those degrees you find or <10, 5, 4 (what I assume is a 5)