First, let's simplify the expression step by step:
(45-20) = 25(15-5) = 10
So, the expression becomes:
25 - 10 = 15
Now, let's simplify the next part:
89 - 10 = 79(20-10) = 10
79 + 10 = 89
Now, the final expression becomes:
15 - 89 = -74
First, let's simplify the expression step by step:
(45-20) = 25
(15-5) = 10
So, the expression becomes:
25 - 10 = 15
Now, let's simplify the next part:
89 - 10 = 79
(20-10) = 10
So, the expression becomes:
79 + 10 = 89
Now, the final expression becomes:
15 - 89 = -74