Stacy is a high school Calculus teacher.  She assigns 45 problems for homework.  There are twice as many multiple choice problems as free response, and 7 more free response than true/false.  How many true/false questions are there?
Let x represent the number of true/false questions
Free response:x+7
Multiple choice: 2(x+7)=2x+14
Total:x+x+7+2x+14=45
4x+21=45
4x=24
x=<<6=6>>6 true/false questions
#### 6