i am going to answer question 1, so q1 is a number line
Answer:
I can't see the numbers well, but the graph is decreasing from (-inf, minimum) and increasing from (minimum, inf). The minimum is the vertex. Hope this helps!
Step-by-step explanation:
Answer:
- P(t) = 100·2.3^t
- 529 after 2 hours
- 441 per hour, rate of growth at 2 hours
- 5.5 hours to reach 10,000
Step-by-step explanation:
It often works well to write an exponential expression as ...
value = (initial value)×(growth factor)^(t/(growth period))
(a) Here, the growth factor for the bacteria is given as 230/100 = 2.3 in a period of 1 hour. The initial number is 100, so we can write the pupulation function as ...
P(t) = 100·2.3^t
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(b) P(2) = 100·2.3^2 = 529 . . . number after 2 hours
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(c) P'(t) = ln(2.3)P(t) ≈ 83.2909·2.3^t
P'(2) = 83.2909·2.3^2 ≈ 441 . . . bacteria per hour
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(d) We want to find t such that ...
P(t) = 10000
100·2.3^t = 10000 . . . substitute for P(t)
2.3^t = 100 . . . . . . . . divide by 100
t·log(2.3) = log(100)
t = 2/log(2.3) ≈ 5.5 . . . hours until the population reaches 10,000
Answer:
Options (3), (4) and (5)
Step-by-step explanation:
1). a² - 9a + 7ab + 63b
= a(a - 9) + 7b(a + 9)
Now we can not solve this problem further.
Therefore, can't be factored by grouping.
2). 3a + 4ab - b - 12
= a(3 + 4b) - 1(b - 12)
We can't solve it further.
Therefore, can't be factored by grouping.
3). ab + 6b - 2a - 12
= b(a + 6) - 2(a + 6)
= (b - 2)(a + 6)
We can be factored this expression by grouping.
4). x³ + 9x²+ 7x + 63
= x²(x + 9) + 7(x + 9)
= (x² + 7)(x + 9)
Therefore, the given expression can be factored by grouping.
5). ay² + a - y² - 1
= a(y² + 1) - 1(y² + 1)
= (a - 1)(y² + 1)
This expression can be factored by the grouping method.
Options (3), (4) and (5) are the correct answers.