Determine which of the following expressions requires combining like terms before it is considered to be in its simplest form. select all situations that apply.

4x + 3y - 7x
a^2 + a^2 - b
5y - x
a^2 + a^2b
-5w^2 + y - 4w^2 - 8y
(-1/2pq)(8pq)

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Ascientist has 50 grams of a radioactive element. the amount of radioactive element remaining after t days can be determined using the equation (1) after two days the scientist receives a second shipment of 50 grams of the same element. the equation used to represent the amount of shipment 2 remaining after t days is 10) - 50 which of the following is an equivalent form of the expression for the amount remaining in shipment 2? what’s the answer?

Adeli owner keeps track of the to-go orders each day. the results from last saturday are shown in the given two-way frequency table. saturday's to-go deli orders in person by phone online total pick up 38 25 31 94 delivery 35 28 34 97 total 73 53 65 191 what percent of the to-go orders were delivery orders placed by phone? a. 14.66% b. 38.41% c. 28.87% d. 52.83%