Is y = 3x + 4 parallel, perpendicular or neither

What is the rate of change of a line that passes through (2,-5) and (6,-2)?

Statements reasons 1. ab ? cd; ad ? bc 1. given 2. ac ? ac 2. reflexive property 3. ? adc ? ? cba 3. ? 4. ? dac ? ? bca; ? acd ? ? cab 4. cpctc 5. ? dac and ? bca are alt. int. ? s; ? acd and ? cab are alt. int. ? s 5. definition of alternate interior angles 6. ab ? cd; ad ? bc 6. converse of the alternate interior angles theorem 7. abcd is a parallelogram 7. definition of parallelogram what is the missing reason in step 3?

For the sequence [tex]a_{n} = 2n/(n+1)[/tex], what is the value of [tex]a_{10}[/tex]