<em>Complete Question:</em>
<em>Which situation illustrates quadratic equation?
</em>
<em>a. The length of a rectangular board is 3m longer than its width and its perimeter is 25m.
</em>
<em>b. Joey paid at least P2,000 for the shirt and pants.The cost of pants is P700 more than the shirt.
</em>
<em>c. A garden's length is 7m longer than its width and the area is 18 square meter.
</em>
<em>d. A lot costbP4,000 per square meter and the area is 120 square meters.</em>
Answer:
C.
Step-by-step explanation:
Required
Determine which option answers the question, correctly.
From the list of given options, only option c answers the question correctly.
This is shown below.
Represent
Length with l and Width with w, such that:
![l = 7 + w](https://tex.z-dn.net/?f=l%20%3D%207%20%2B%20w)
Area (A) is calculated as thus:
![A = l * w](https://tex.z-dn.net/?f=A%20%3D%20l%20%2A%20w)
Substitute 7 + w for l and 18 for A.
This gives:
![18 = (7 + w) * w](https://tex.z-dn.net/?f=18%20%3D%20%287%20%2B%20w%29%20%2A%20w)
Open Bracket
![18 = 7w + w^2](https://tex.z-dn.net/?f=18%20%3D%207w%20%2B%20w%5E2)
Reorder
![w^2 + 7w = 18](https://tex.z-dn.net/?f=w%5E2%20%2B%207w%20%3D%2018)
Subtract 18 from both sides
![w^2 + 7w - 18= 18 - 18](https://tex.z-dn.net/?f=w%5E2%20%2B%207w%20-%2018%3D%2018%20-%2018)
![w^2 + 7w - 18= 0](https://tex.z-dn.net/?f=w%5E2%20%2B%207w%20-%2018%3D%200)
See that the above expression is a quadratic equation.