Answer:
Step-by-step explanation:
$1800 is spent on a washing machine. This number never changes, so we just need to add that to our annual total
$89 is spent every year. This means that this number needs to be with our variable, x, as it is dependent on the number of years that occur. When we put these two things together, we get the following equation:
The wall area is the product of the room perimeter and the room height:
A₁ = (2*(12.5 ft + 10.5 ft))*(8.0 ft) = 368 ft²
The window and door area together is
A₂ = 2*((4 ft)*(3 ft)) + (7 ft)*(3 ft) = 45 ft²
The area of one roll of wallpaper is
A₃ = (2.5 ft)*(30 ft) = 75 ft²
Then the number of rolls of wallpaper required will be
1.1*(A₁ - A₂)/A₃ ≈ 4.74
5 rolls of wallpaper should be purchased.
_____
As a practical matter, not much of the window and door area can be saved. The rolls are 30 inches wide, but the openings are 36 inches wide. Some will likely have to be cut from two strips. The strips will have to be the full length of the wall, and the amount cut likely cannot be used elsewhere. If the window and door area cannot be salvaged, then likely ceiling(5.4) = 6 rolls will be needed (still allowing 10% for matching and waste).
Using math skills to answer a question
Answer:
C
Step-by-step explanation:
The equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
here (h, k) = (5, 2), thus
y = a(x - 5)² + 2
To find a substitute (4, - 3) into the equation
- 3 = a + 2 ⇒ a = - 3 - 2 = - 5
y = - 5(x - 5)² + 2 ← in vertex form
Expand (x - 5)² and distribute by - 5
y = - 5(x² - 10x + 25) + 2
= - 5x² + 50x - 125 + 2
= - 5x² + 50x - 123 ← in standard form
