Answer these questions

1.Combine like terms.

7x² + 3(x² − 1) =

2.Combine like terms.
7a⁵ − 3a⁵ + 7b + b =

3.Combine like terms.
9m + 16 − 12 + 3n =

4.Combine like terms.
4b + 8b − 13 =

5.Combine like terms.
y + 4 + 9(y + 9) =

6.Combine like terms.
7y² + 7(4y² − 3) =

7.Use the information in the table to enter a simplified expression to find the total weight of the medals won by the top medal-winning nations in the 2012 London Olympic Games.

The three types of medals have different weights. Use g, s, and b as the variables for the weight of gold, silver, and bronze, respectively.

2012 Summer Olympics
Gold Silver Bronze
United States 46 29 29
China 38 27 23
Great Britain 29 17 19

An expression for the total weight of the medals won is