The problem says that the expression (3x + 5)(5x − 1) <span>represents the area of the floor of the building in square meters. Therefore, to solve this problem you have to follow the proccedure shown below.
1. First, to simplify the expression (3x + 5)(5x − 1) you must apply the distributive property. Then, you obtain:
15x</span>²-3x+25x-5
2. Then, you have:
15x²+22x-5
3. As you can see, the correct answer is the last option: 15x²+22x-5
If order mattered, we would say select the first number (10 choices), then the second (9 choices) then the third (8 choices). So there would be 10 x 9 x 8 = 720 possible choices.
