Pacho starts saving for college by opening a savings account and depositing $50. he plans to make a deposit every month to continue saving. the amount of money in pacho's savings account can be modeled by the sequence a0=50, an=an−1 + 25, where n is the number of months since his initial deposit. is the sequence an a function? why or why not?

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?