Following the order of operations (PEMDAS):
Step 1: simplify what’s inside the parentheses. Since we don’t know either variable s or t, we can’t simplify any further from what it already is.
Step 2: distribute the 5 to each of the terms inside the parentheses. This gets you (5s - 10t)
Step 3: arrange your final answer:
7 + 5s - 10t
You can’t simplify any more unless you know one the the variables so you are left with this.
