Area of the rectangle = x² - 3x - 10
2019
Step-by-step explanation:
Length of the rectangle = x + 2
Width of the rectangle = x - 5
Area of the rectangle = length × width
= (x + 2) (x - 5)
= x² + 2x - 5x - 10
= x² - 3x - 10
Area of the rectangle = x² - 3x - 10
C = 20t² + 135t + 3050
Where
C = the number of new cars
t = year the number of new cars was purchased
t = 0 corresponds to 1998
Find the when c = 15,000
C = 20t² + 135t + 3050
15,000 = 20t² + 135t + 3050
20t² + 135t + 3050 - 15,000 = 0
20t² + 135t - 11,950 = 0
4t² + 27t - 2390 = 0
Solve using quadratic equation
t = -b ± √b² - 4ac / 2a
= -27 ± √27² - 4(4)(-2390) / 2(4)
= -27 ± √729 -(-38240) / 8
= -27 ± √729 + 38240 / 8
= -27 ± √38969 / 8
= -27/8 + √38969/8 or 27/8 - √38969/8
= -3.375 + 197.41/8 or -3.375 - 197.41/8
= -3.375 + 24.67625 or -3.375 - 24.67625
t = 21.30125 or - 28.05125
t cannot be negative
Therefore,
t = 21.30125
To the nearest whole number
t = 21
Recall,
t = 0 corresponds to 1998
Therefore
1998 + 21 = 2019
c = 15,000 in the year 2019
