6. A group of students was given the following to simplify: 3x+7. Brian believes that this expression simplifies to 10x because you add the 3 and 7 together and bring the x. Lindanes believes that this expression simplifies to 10 because you add the 3 and 7 and drop the x. Marcos believes that this expression simplifies to 3x+7 because you cannot combine the two terms. Jasmine believes that this expression simplifies to 21x because you multiply 3 and 7 and bring the x. Which student is correct?