7n-(4n-3) simply to create a equivalent expression?

If 1 is divided by the sum of y& 4.the result is equal to 3 divided by 4, find the value of m

Polynomial that can be factored as (3x-4)(3x+4)

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.