Simplify Expressions Combine Like Terms

Which of these are like terms in the following expression:
3x + 7 - 9x + 24y + 2x²

• 7, 24y

• 3x, 9x

• 3x, -9x

• 3x, -9x, 2x²

Simplify:

5a + 3a

• 8a

• 15a

• 7a

• 10a

Simplify:

4x + 5 + x + 3

• 4x + 8

• 5x + 8

• 4x + 15

• 5x + 15

Simplify:

5.2a + 3 + 2.1a - 5

• 7.3a - 2

• 7.3a + 2

• 7.3a - 8

• 8.3a - 2

Simplify:

5(x + 3)

• 5x + 15

• 5x + 8

• 5x + 3

• 20x

• 5a + 30b - 20c

• 5a + 20b - 25c

• 20a + 60b - 25c

• 5a + 15b - 25c

Simplify:

8a + 3 - 5a + 1

• 13a + 4

• 13a + 2

• 3a + 4

• 3a + 2

Simplify:

-4(a - 2)

• -4a + 8

• -4a - 8

• 12a

• -4a - 6

Simplify:

25(x - 2y + 3)

• 25x - 50y + 80

• 25x + 23y + 28

• 25x - 50y + 75

• 25x + 50y + 75