I think x=10
4x=3x+10
subtract 3x from both sides and you get x=10
Choice A is one of the answers. Nice work. This is because x+x+x turns into 3x.
Choice D is the other answer because 2(x+1) + x = 2x+2+x = 3x+2. You can find this through trial and error. Or you could graph y = x+x+x+2 and y = 2(x+1)+2 to find that they are the same exact identical diagonal line. A non-graph approach would be to set up a table of values to see that the two tables are identical.
Answer: Same-side interior angles are NOT always congruent.
