Question

Please help. I need to know the strategy, the correct work, and to identify the error.

Answer 1

Answer:

See below

Step-by-step explanation:

13x + 5 + 17x - 4.5 + x

NOTE: You can only add/subtract LIKE terms . Here we have  variable terms in x  (13x , 17x and x) and 2 constants ( 5 and 4.5).

Sarah's next line is

18x + 17x - 4.5 + x

This is incorrect . It looks like she  added 13x + 5 and got 18x!! Which is of course wrong because they are NOT LIKE terms. 5 is a constant and 13x is a variable term in x.

The third line is correct:-

35x - 4.5 + x.

She has added the 2 variables 17x and 18x.

Fourth line  is  30.5x + x. She's at it again - Trying to subtract 4.5 from 35x .

Last line 31.5x

She has added  the 2 terms in x correctly, but the final answer is wrong of course due to the earlier errors.