Answer:
2x+3
Step-by-step explanation:
Since her brother is m years old, you would have to multiply her brother's age by 2 since the question says "...twice here brother's age." This part would equal to the equation 2x. The question also says " ...3 years more..." This would change the equation with the addtion of 3. The completed problem would then be 2x+3. Hope this helped!