Part 1: Math is like another language! Let's translate "The difference between three times a number and seven more than two times the number." "A number" is a variable, let's use x. "The difference between __ and __" means the first blank minus the second blank: so, (three times x) - (seven more than two times x). "More" means to add, and "times" means to multiply. So, the answer is 3x - (2x+7). By the way, I switched 7 and 2x to satisfy standard form.
Part 2: Our expression is 3x - (2x+7). Now, we need to simplify this. First, remove the parentheses: 3x-2x+7. Now, 3x and 2x are LIKE TERMS because they both have "x" in them, so you can subtract their coefficients--that is, 3 and 2. 3x-2x=(3-2)x=1x=x. Substitute that in, and we get our answer: x+7.
Answers: 3x-(2x+7); x+7