2(w+h)=perimeter
2((7x-5)+(5x+10))
1. Simplify
2(7x-5+5x+10)
2. Collect like terms
2((7x+5x)-5+10)
3. Simplify
2(12x-5+10)
4. Simplify
2(12x+5)
5. Distribute
2*12x+2*5
6. Simplify
24x+2*5
7. Simplify
24x+19
The perimeter of the rectangle is 24x+10, have a nice day :D