Distribute the 5 to each of the numbers so you should get 5x+5+5x+5+5x+35. after this you should combine like terms, all of the 5’s & the 35 and 5x’s. you should have 15x+45. then you divide 45 by the 15 and you should get x=3
It helps you know if the answer is reasonable because when you do the work and get your answer, you can check if it is close to your estimate, and if it is, it is most likely correct. On the other hand if it is not close to the estimate it is most likely wrong, unless you estimated incorrectly.
