Alright, absolute value means basically the true value of a number. Let's say -100 for instance. It may be a negative, but it's still WORTH 100 in value, negative or not. Absolute value makes every number a positive whole number, so -100 would be 100
So, 2-7 is equal to -5. But is it? Nope, absolute value gives it the value of +5, or basically 5. Your answer is 5.