4/7 divided by 4 i can’t get the answer correct

The angle of a triangle are given as 6x,(x-3), and (3x+7). find x then find the measures of the angles

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

Don't know how to find x given these segment lengths