The interior angles of a parallelogram will always equal 360. The interior angles of a triangle are 180 if it is a equilateral triangle then the angles are 60 degrees each. You know 2 sides of parallelogram. The 100 degree and 90 degree. You can find the one opposing the x because it’s on a straight line and a straight line is 180 degrees if a triangle is 60 degree angle then the opposing angle to complete the straight line must be 180-60 so you get 120. You now know 3 sides. 120, 90 and 100 They should add up to be 360 so you can set up an equation like so 120+90+100+x=360 And x = 50
First, graph both equations on a rectangular coordinate system (see attached screenshot). Then, simply figure out where these two lines intersect. Since they intersect at (2,3), x=2 and y=3.
Plugging these values in the equations for x and y, you can see if these are the correct answers:
(3)=3(2)-3, (2)+(3)=5
Since both of these are true, you have the right answer.