First, let's use the given condition that a + b = 7 to find the values of a and b.
a + b = 7a = 7 - b
Now, substitute the value of a in the expression:
3(28 + 7 - b) - 73(7 - b) + 8b3(35 - b) - 511 + 73b + 8b105 - 3b - 511 + 81b + 8b-406 + 86b
Therefore, the simplified expression is -406 + 86b.
First, let's use the given condition that a + b = 7 to find the values of a and b.
a + b = 7
a = 7 - b
Now, substitute the value of a in the expression:
3(28 + 7 - b) - 73(7 - b) + 8b
3(35 - b) - 511 + 73b + 8b
105 - 3b - 511 + 81b + 8b
-406 + 86b
Therefore, the simplified expression is -406 + 86b.