Answer:
b
Step-by-step explanation:
8x +4(x -1)
<em>Expand by multiplying 4 into each term inside the bracket:</em>
= 8x +4(x) +4(-1)
= 8x +4x -4
<em>Simplify</em>
= 12x -4
Thus, the answer is b.
Answer:
24
Step-by-step explanation:
Total cost is 220 dollars. This is because 3 times 60 is 180 and plus membership fee of 40 dollars is 220 dollars.
Answer:
$1200
Step-by-step explanation:
Let the roof be square shaped
Area of the roof = L²
L is the side length of the roof
Given
L = 40ft
Area of the roof = 40²
Area of the roof = 1600ft²
If plants used for a green roof cost $0.75 per square foot, this means
1 ft² = $0.75
Let the cost needed to cover both sides of the roof be y, hence;
1600ft² = y
Divide both expressions
1/1600 = 0.75/y
y × 1 = 0.75×1600.
y = 0.75×1600
y = 1200
Hence it will cost $1200 to cover both sides of the roof
You can solve this problem by following the steps below:
1. You need the formula for calculate the area of a circle, which is:
A=πr²
"A" is the area of the circle
"r" is the radius of the circle (r=35 centimeters).
2. Now, you must take the derivative. Then, the rate of change of the area is:
dA/dt=(2πr)(dr/dt)
3. The radius of change of the radius "r" with respect to time, is:
dr/dt=6 cm/min
4. Then, you have:
dA/dt=(2πr)(dr/dt)
dA/dt=2π(35 cm)(6 cm/min)
dA/dt=420π cm²/min
