Final answer:
The expression 2a+3(a+7)−(3a+3) simplifies to 2a + 18.
Step-by-step explanation:
The expression 2a+3(a+7)−(3a+3) can be simplified by applying the distributive property and combining like terms.
First, distribute the 3 to both terms inside the parentheses: 2a + 3a + 21 - 3a - 3.
Next, combine like terms: 2a + 3a - 3a + 21 - 3 simplifies to 2a + 21 - 3.
Finally, combine the constants: 21 - 3 = 18.
Therefore, the simplified expression is 2a + 18.