18 + 7 + (18 + 2x) + 7
25 + (18 + 2x) + 7
32 + (18 + 2x)
32 + 18 + 2x
50 + 2x
2x + 50 since first we write the ''x'' term first
It's just a question of adding like terms. Since 2x is the only term with an x, and all the rest are plus signs, we just add together all the numbers that don't have an x next to them.