i know the answer but need work.

Translate the word phrase into a math expression. 15 fewer than the product of 4 and a number. (pls immediately)

Asif spent $745.10 on 13 new file cabinets for his office. small file cabinets cost $43.50 and large file cabinets cost $65.95. write and solve a system of equations to find the number of small cabinets and large cabinets he purchased. determine if each statement is true or false. 1. he purchased 5 small cabinets. true or false 2. he purchased 7 large cabinets. true or false 3. he spent $527.60 on large cabinets. true or false

Find the solution of this system of equation -7x+y=-20 9x-3y=36