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lions [1.4K]
3 years ago
8

Multiply: (5t - 4)(4t + 5)

Mathematics
1 answer:
ANEK [815]3 years ago
5 0

Answer:

A. 20t² + 9t - 20

Step-by-step explanation:

(5t × 4t) + (5t × 5) - (4 × 4t) - (4 × 5)

= 20t² + (25t - 16t) - 20

= <u>20t² + 9t - 20</u> (A)

<em>Hope </em><em>this </em><em>is </em><em>h</em><em>e</em><em>l</em><em>p</em><em>ful </em><em>and </em><em>useful </em><em>:</em><em>)</em>

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Triangle BCD is rotated counterclockwise to form
IRISSAK [1]

Answer:

The answer is 90 degrees. Have a good day!

Step-by-step explanation:

6 0
3 years ago
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Suppose that c(x)= (7x^3) - (84x^2) + (22,000x) is the cost of manufacturing x items. Find a production level that will minimise
ra1l [238]

Answer:

54

Step-by-step explanation:

4 0
3 years ago
It is desired to compare the hourly rate of an entry-level job in two fast-food chains. Eight locations for each chain are rando
notka56 [123]

Answer:

It can be concluded that at 5% significance level that there is no difference in the amount paid by chain A and chain B for the job under consideration

Step by Step Solution:

The given data are;

Chain A 4.25, 4.75, 3.80, 4.50, 3.90, 5.00, 4.00, 3.80

Chain B 4.60, 4.65, 3.85, 4.00, 4.80, 4.00, 4.50, 3.65

Using the functions of Microsoft Excel, we get;

The mean hourly rate for fast-food Chain A, \overline x_1 = 4.25

The standard deviation hourly rate for fast-food Chain A, s₁ = 0.457478

The mean hourly rate for fast-food Chain B, \overline x_2 = 4.25625

The standard deviation hourly rate for fast-food Chain B, s₂ = 0.429649

The significance level, α = 5%

The null hypothesis, H₀:  \overline x_1 = \overline x_2

The alternative hypothesis, Hₐ:  \overline x_1 ≠ \overline x_2

The pooled variance, S_p^2, is given as follows;

S_p^2 = \dfrac{s_1^2 \cdot (n_1 - 1) + s_2^2\cdot (n_2-1)}{(n_1 - 1)+ (n_2 -1)}

Therefore, we have;

S_p^2 = \dfrac{0.457478^2 \cdot (8 - 1) + 0.429649^2\cdot (8-1)}{(8 - 1)+ (8 -1)} \approx 0.19682

The test statistic is given as follows;

t=\dfrac{(\bar{x}_{1}-\bar{x}_{2})}{\sqrt{S_{p}^{2} \cdot \left(\dfrac{1 }{n_{1}}+\dfrac{1}{n_{2}}\right)}}

Therefore, we have;

t=\dfrac{(4.25-4.25625)}{\sqrt{0.19682 \times \left(\dfrac{1 }{8}+\dfrac{1}{8}\right)}} \approx -0.028176

The degrees of freedom, df = n₁ + n₂ - 2 = 8 + 8 - 2 = 14

At 5% significance level, the critical t = 2.145

Therefore, given that the absolute value of the test statistic is less than the critical 't', we fail to reject the null hypothesis and it can be concluded that at 5% significance level that chain A pays the same as chain B for the job under consideration

3 0
3 years ago
Please help ! This is 7th grade math and I’ve been stuck on this question for 30 minutes!
FinnZ [79.3K]

\dfrac{1}{22}\:\dfrac{\text{in}}{\text{hr}}

Step-by-step explanation:

The amount of time from 10pm to 7am is 9 hours. However, the time indicated is 7:10am. Since there are 60 minutes in an hour, 10 min is equal to 1/6 of an hour. Therefore, the total time that the water level of the pool decreased is 9\frac{1}{6} hours or \frac{55}{6} hours. To find the rate at which the water level decreased, we divide the change in the water (in inches) by the time it took to reach that level. So we write

rate of change = \dfrac{\text{change\:in\:height}}{\text{change\:in\:time}}

\:\:\:\:\:\:\:= \dfrac{\frac{5}{12}\:\text{in}}{\frac{55}{6}\:\text{hrs}}

\:\:\:\:\:\:\:=\dfrac{5}{12}\cdot\dfrac{6}{55}\:\dfrac{\text{in}}{\text{hr}}

\:\:\:\:\:\:\:= \frac{1}{22}\:\dfrac{\text{in}}{\text{hr}}

7 0
3 years ago
The sum is a prime number the sum is less than 4
Liula [17]
The sum is 3 or 1 , 3 is a prime number and 1 is a prime number. But the most reasonable answer/sum is 3
7 0
3 years ago
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