Answer:
(2x - 3)(2x + 3)
Step-by-step explanation:
Given
4x² - 9
This is a difference of squares and factors in general as
a² - b² = (a - b)(a + b)
4x² = (2x)² ⇒ a = 2x
9 = 3² ⇒ b = 3, thus
4x² - 9 = (2x - 3)(2x + 3) ← in factored form
A and b are the minutes spent on machine A and machine B, respectively.
a+b = 40
b = 40-a
8a + 6b = 300
8a + 6(40-a) = 300
8a + 240 - 6a = 300
2a = 60
a = 30
b = 40-a = 10
30 minutes on machine A and 10 minutes on machine B
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Answer:
C. 16ft by 4ft
Step-by-step explanation: