Algebraic expression

Simplify the following expression:
a - 8 - 10

• 2a - 18
• a - 18
• a - 2
• a + 18

Simplify by combining like terms:
5a + 2b - 3a + 4

• 8a + 2b + 4
• 2a + 2b + 4
• 8ab
• 4ab + 4

Simplify the Expression: 2x + 3x - 12x

• 7x
• -7x
• -17x
• 17x

5z - z - z -z =

• 2z
• 3z
• 4z
• z

r + r + r + 12 + 7 =

• r + 19
• 3r - 5
• 3r + 19
• 2r + 5

3f + 4f + 5f + 6f - 7f =

• 25f
• 12f
• 11f
• 24f

Identify the "like terms" in the expression: 
2x + 4y - 3x + y - x

• 2x and 4y and -3x
• 2x and -3x and x
  4y and y 
• they are all like terms
• there are no like terms

Simplify:
17 + 7h - 19 + 14h

• 21h + 36
• 21h - 2
• 7h + 36
• 7h - 2

Simplify the expression: 3x + 2x

• 5x
• x
• 6x
• 5

x + 2x

• 2x²
• 3x
• Can't be simplified
• 3x + x