Evaluate the following expression when x = 3 and y = 4:
2 answers:
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Answer:
Step-by-step explanation:
x² = 19x + 12
⇔ x² - 19x - 12 = 0
Calculating the discriminant :
b² - 4ac = (-19)² - 4×1×(-12) = 409
The discriminant is positive ,then the equation has two solutions.
Answer:
The percentage increase in bird population in the second years is 4% .
Step-by-step explanation:
Given as :
During two years, the population of birds of an island became 7 times more than before.
The the percentage increase in first year = = =40%
Let The percentage increase in second year = = r%
So, According to question
The initial population of bird = x
The increase population of bird =7 times before = 7 x
Now,
The increase population of bird = initial population of bird × (1+ ) × (1+
)
Or, 7 x = x × (1+ ) × (1+
)
Or, = 1.4 × (1+
)
Or, 7 = 1.4 × (1+ )
Or, = (1+
)
Or, 5 = (1+ )
Or, (1+ ) = 5
Or, = 5 - 1
Or, = 4
∴ r = 4 × 100
I.e r = 400
so, The percentage increase = r% = 4
Hence The percentage increase in bird population in the second years is 4% . Answer