DEFINITION OF LIKE TERMS: Same variables raised to the same powers
5:
7 + 19t - 6t
7 + 13t
3:
8 + 16r - 9r
8 + 7r
4:
5/6x - 2/3x
5/6x - 4/6x
1/6x
Because you only need a common denominator for subtraction & addition, but you do NOT need a common denominator when multiplying or dividing. So, 6 is the common denominator. So, I multiplied both 2 & 3 by 2 to get the same denominator. then, I subtracted 5/6x - 4/6x & got 1/6x as an answer.
1:
10y & -9y are like terms because they have the same variables
2:
-7w & 3w are like terms because they have the same variables
Hope this helps you!!! :)