Help me with long math equation not hard

It’s -22y + 3z

You get this by first distributing 3 to get rid of the parenthesis

Which then leaves you with -4y + 9z -18y -6z

Then you collect the like terms

Which leaves you with your answer

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.