Answer:
D. Subtract 5 from both sides
Explanation:
When you are solving for a variable, you want to use reverse PEMDAS (Parenthesis first, Exponents second, Multiplication/Division third, Addition/Subtraction last), which is SADMEP (Subtraction/Addition first, Division/Multiplication second, Exponents third, Parenthesis last). So the first step in the equation 5 + 10x = 20 would be to subtract 5 from both sides.