Answer:

Step-by-step explanation:

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
A hexagon can be considered to be 6 triangles with a common vertex.
Area of 1 of the triangle = 1/2 * 2 * side length
Area of whole hexagon is 6 times this.
In this problem, volume is computed:
volume = ∫(flow rate)·dt
.. = ∫[0, t] (3/10)*sin(2πt/7)·dt
= (3 / 10)*(7 /(2 π))*(-cos (2 π t/7)+1)
= (-21 / (20 π))*(cos (2 π t /7) - 1)
Volume is equal to 21 sin^2 (pit/7) / 10pi is the inhaled air in the lungs at time t