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?
Define a variable ** Let x represent the number of true/false questions
How many free response problems are there? ** Free response:x+7
How many multiple choice problems are there? ** Multiple choice: 2(x+7)=2x+14
Write an equation ** Total:x+x+7+2x+14=45
Combine like terms ** 4x+21=45
Subtract 21 from each side ** 4x=24
Divide by 4 ** x=<<6=6>>6 true/false questions
#### 6