Answer:
3x+4
Explanation:
When simplifying expressions, you need to combine like terms. 5x and -2x combined would equal 3x. Since the 2x was negative, you needed to subtract. Next, you combine 3 and 1, which should equal 4.
When putting the expression back together, make sure you leave it in the same order as received. This would mean you would put the coefficient with the variable first, and then put the whole number.
Make sure to take the signs into account. If it is negative, you subtract, and if it is positive, you add.
Hope I helped!