They are both correct! Michael's equation is just a distributed version of Laurie's equation. Laurie's equation is solved like this: First distribute to get
2x + 1.2 + 0.8 + 0.7, then add the numbers together to get 2x + 2.7.
Michael's equation also starts with distributing to get 2x + 1.2 + 0.8 + 0.7 and adding the numbers together to get the same answer: 2x + 2.7. Hope this helps!
