Brian assembled four toy train cars on a track. how many different ways could he have ordered the cars?

This is so harddd! solve. 1 + 1 = solve 4 + 4 = solve 3 x 3

Solve 2x+y=3 x+y=5 in substitution method

Match the following reasons with the statements given to create the proof. 1. do = ob, ao = oc sas 2. doc = aob given 3. triangle cod congruent to triangle aob vertical angles are equal. 4. 1 = 2, ab = dc if two sides = and ||, then a parallelogram. 5. ab||dc if alternate interior angles =, then lines parallel. 6. abcd is a parallelogram cpcte