Question

use mulitplying by 1 to find an expression equivalent to (10/13) with a denominator of 39a

Thank you for your help.

Answer 1

ask yourself
"What did I multiply 13 by to get 39a ?"

How about 10/13 * 3a/(3a) = (30a)/(39a)

Answer 2

Provide an example of at least five ordered pairs that do not model a function. The domain will be any five integers between 0 and 20. The range will be any five integers between -10 and 10. Your example must not be the same as those of other students or the textbook. Why does your example not model a function?