x+2y=200
x=y+50
if x + 2y = 200, then let's solve it for x...
x = 200 - 2y (subtracted 2y from both sides)
Now we have two "x +" equations"
x = y + 50
x = 200 - 2y
If x equals two things, those two things equal each other (transitive property)
y + 50 = 200 - 2y
3y + 50 = 200 (added 2y to both sides)
3y = 150 (subtracted 50 from both sides)
y = 50.
if y = 50, sub 50 back in for y into either of the two original equations (how about both to check?)
x + 2(50) = 200
x + 100 = 200
x = 100
x = 50 + 50
x = 100
it's the same, so x = 100, y = 50
The lines cross at (100, 50)
hopes this helps :) :D :)
