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3 years ago

Multiply (9 - 4i)(2 + 5i)

Mathematics

1 answer:

LenaWriter [7]3 years ago

4 0

Answer:

38+37i

Step-by-step explanation:

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5x + 6y = 20 , 8x - 6y = -46

serg [7]

Answer:

5x + 6y = 20_____(1)

8x - 6y = -46_____(2)

Solving simultaneously:

Eqn(1) + Eqn(2)

5x + 8x + 6y + (-6y) = 20 + (-46)

13x = -26

x = -2

substituting this into Eqn (1):

5(-2) + 6y = 20

-10 + 6y = 20

6y = 30

y = 5

hence:

x = -2,y = 5.

7 0

3 years ago

The area of a rectangle is represented by x^2-5c-14. What are the dimensions?

jekas [21]

The dimensions are factors of the expression
... you multiply them together to get the area

the factors are ... (x - 7) & (x + 2)

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3 years ago

Mark wants to hang four rectangular pictures in a row on a wall so that the horizontal space between each picture is always the

Kisachek [45]

9 inches
12+12+9+9+8+8+8+8=74
12+12=24
9+9=18
8+8+8+8=32
24+18+32=74

5 0

3 years ago

Read 2 more answers

Determine whether the proportion is true or false 15/33 equals 22 / 46

Juliette [100K]

Answer:

False

Step-by-step explanation:

It could be solved using the proportion method i.e multiply 15 by 46 and 33 by 22. Since the answer is not equal, it's false.

6 0

3 years ago

Read 2 more answers

In Pennsylvania the average IQ score is 101.5 The variable is normally distributed and the population standard deviation is know

elena-14-01-66 [18.8K]

Answer:

P-value = 0.0368

Step-by-step explanation:

We are given the following in the question:

Population mean, μ = 101.5

Sample mean, $\bar{x}$ = 106.4

Sample size, n = 30

Alpha, α = 0.05

Population standard deviation, σ = 15

First, we design the null and the alternate hypothesis

$H_{0}: \mu = 101.5\\H_A: \mu> 101.5$

We use One-tailed(right) z test to perform this hypothesis.

Formula:

$z_{stat} = \displaystyle\frac{\bar{x} - \mu}{\frac{\sigma}{\sqrt{n}} }$

Putting all the values, we have

$z_{stat} = \displaystyle\frac{106.4 - 101.5}{\frac{15}{\sqrt{30}} } = 1.789$

Now, $z_{critical} \text{ at 0.05 level of significance } = 1.64$

Since,

$z_{stat} > z_{critical}$

We reject the null hypothesis and accept the alternate hypothesis. Thus, students in Pennsylvania have an IQ that is significantly greater than the state average.

P-value can be calculated with the standard normal table.

P-value = 0.0368

P-value is lower than the significance level.

4 0

3 years ago

Multiply (9 - 4i)(2 + 5i)​

Multiply (9 - 4i)(2 + 5i)