Explain how to decide if a proportion is true or false. Please include an example : A proportion is an equation comparing two ratios. If the ratios are identical, the proportion is true. If not, the proportion is false.

explain how i got the answer and include example to go with answer above break down how you would got the example

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

Ineed on this question me get the answer

Simplify the algebraic expression 8y-2(y+4)