Do you have to use substitution?
Answer:
1. Sides 1 and 2 are congruent so sides 3 are also congruent
2. Since angles D and R are the same and the two sides are the same, the triangles are the same
Plug in 0 into x of the equation y=2x+3, solve it, then take that answer and use that as your y then plug in the answer for y and solve for x. (i realized i am very bad at explaining this over this. Sorry I tried)