6 acts as the base. 15 acts as the height, because it extends from the base to meet vertex opposite the base at a 90° angle.
General formula for triangle area
a = 1/2 × b × h
plug in the numbers
a = 1/2 × 6 × 15
a = 90/2
a = 45
The area of the triangle is 45 units²
Part A:
Given that <span>the mattress is sold for 50% off of the retail price, let the retail price of the mattress be x, then
50% of x = 1200
⇒ 0.5x = 1200
⇒ x = 1200 / 0.5 = 2400
Therefore, </span><span>the retail price of the mattress, before the discount is $2,400.
Part B:
Given that </span><span>the store marks up the retail price to 150% of the wholesale price. Let the whole sale price be p, then
(100% + 150%) of p = 2400
250% of p = 2400
2.5p = 2400
p = 2400 / 2.5 = 960.
Therefore, </span><span>the wholesale price, before the markup was $960</span>
The figure is represented by the inequality y ≥ 5 · x² - 40 · x - 45. (Correct choice: C)
<h3>What inequality represents the figure</h3>
In accordance with the figure, we have an inequation of the form y ≥ f(x). Now we proceed to find the <em>quadratic</em> equation of the parabola:
f(x) = a · (x + 1) · (x - 9)
- 125 = a · (4 + 1) · (4 - 9)
- 125 = a · 5 · (- 5)
- 125 = - 25 · a
a = - 5
f(x) = 5 · (x + 1) · (x - 9)
f(x) = 5 · (x² - 8 · x - 9)
f(x) = 5 · x² - 40 · x - 45
The figure is represented by the inequality y ≥ 5 · x² - 40 · x - 45. (Correct choice: C)
To learn more on inequalities: brainly.com/question/17675534
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