Question

Could someone explain this

Answer 1

it’s basically asking you to put together the ones that have the same variable ! for example in #1 you have :
9d + 3y - 5g + 9g - 5 :

The only variable that is seen more than once is g. So you’d combine -5g + 9g

which would give you +4g, therefore:

#1. = 9d + 3y + 4g - 5

you could also use combine like terms calculator on wolframalpha.com, but I would suggest knowing what you’re doing so you can pass your tests!

Answer 2

so like terms for example are 2x and 8x what makes them alike are their variable so if you have a term that is 2x and 7p those are NOT like terms because their variables are different