Jade solved the following equation:

3 + 5x – 7 = 3x – 9

step work justification
1 5x + 3 – 7 = 3x – 9 commutative propertyof addition
2 5x – 4 = 3x – 9 addition property of equality
3 2x – 4 = –9 subtraction property of equality
4. 2x = –5. addition property of equality
5. x = –2.5. division property of equality

which step has an incorrect justification?
step 4
step 3
step 2
step 1