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2 years ago

Write an equivalent expression for (x - 11)(x + 9).

Mathematics

1 answer:

vodka [1.7K]2 years ago

7 0

Answer:

x²-2x-99

Step-by-step explanation:

(x-11)(x+9) - foil method

x times x = x squared

x times 9 = 9x

-11 times x = -11x

-11 times 9 = -99

x squared + 9x + 11x + -99

x squared-2x-99

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Find the mean, the median, and all modes for the data in the given frequency distribution. (Round your answers to one decimal pl

kvasek [131]

Answer: Mean = 7.8

Median = 9

Mode = 2,9

Step-by-step explanation: Mean is the average value of a data set. Mean from a frequency table is calculated as:

$E(X)=\frac{2(10)+3(9)+9(10)+11(7)+12(3)+15(4)+16(3)}{10+9+10+7+3+4+3}$

E(X) = 7.8

Mean for the given frequency distribtuion is 7.8.

Median is the central term of a set of numbers. Median in a frequency table is calculated as:

1) Find total number, n:

n = 10 + 9 + 10 + 7 + 3 + 4 + 3 = 46

2) Find position, using: $\frac{n+1}{2}$

$\frac{n+1}{2}=\frac{47}{2}$ = 23.5

Median is in the 23.5th position.

3) Find the position by adding frequencies: for this frequency distribution, 23.5th position is 9

Median for this frequency distribution is 9.

Mode is the number or value associated with the highest frequency.

In this frequency distribution, 2 and 9 points happen 10 times. So, mode is 2 and 9.

Mode for this distribution is 2 and 9.

7 0

3 years ago

Hamburger sells 3 pounds for six dollars if Samantha 510 pounds of hamburger how much will she pay

Lina20 [59]

I believe you meant to say that if Samantha bought 510 pounds of hamburger, how much will she pay?

Now from the information we already have, we know that 3 pounds of hamburger will cost 6 dollars.

The next thing we need to know is how much one pound of hamburger will cost. This will help us calculate how much the rest will cost.

we now form an equation to assist us.
3 = 6
1= x

(where x represents the unknown price of one pound of hamburger)

Now we must cross-multiply:

3 * x = 6 x 1

3x = 6

x = 6/3

x = 2

therefore one pound of hamburger costs 2 dollars.

Now, If one pound costs 2 dollars, how about 510 pounds?

We simply multiply: 510 x 2 = 1,020

Therefore Samantha will pay 1, 020 dollars for 510 pounds of hamburger.

5 0

3 years ago

Is 0.09 greater than 0.7

chubhunter [2.5K]

No, 0.7 is greater than 0.09

0.70 > 0.09

hope this helps

3 0

3 years ago

Read 2 more answers

2. Carl needs 15 hours longer than Jennifer to paint a room. If they work together, they can complete the job in 4 hours. Explai

nasty-shy [4]

Answer:

Jennifer would complete the job on her own in 5 hours.

Step-by-step explanation:

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

$ax^{2} + bx + c, a\neq0$ .

This polynomial has roots $x_{1}, x_{2}$ such that $ax^{2} + bx + c = a(x - x_{1})*(x - x_{2})$ , given by the following formulas:

$x_{1} = \frac{-b + \sqrt{\Delta}}{2*a}$

$x_{2} = \frac{-b - \sqrt{\Delta}}{2*a}$

$\Delta = b^{2} - 4ac$

Rates

The together rate is the sum of their separates rate.

We have that:

Jennifer takes x hours to complete the job on her own, so her rate is 1/x.

Carl needs 15 hours longer than Jennifer, that is, 15 + x hours, so his rate is 1/(15+x).

The together rate is 1/4. So

$\frac{1}{4} = \frac{1}{x} + \frac{1}{15+x}$

$\frac{1}{4} = \frac{15 + x + x}{x(15+x)}$

$\frac{1}{4} = \frac{15 + 2x}{x(15+x)}$

Applying cross multiplication.

$x^2 + 15x = 4(15 + 2x)$

$x^2 + 15x = 60 + 8x$

$x^2 + 7x - 60 = 0$

Quadratic equation with $a = 1, b = 7, c = -60$ . So

$\Delta = 7^{2} - 4*1*60 = 289$

$x_{1} = \frac{-7 + \sqrt{289}}{2} = 5$

$x_{2} = \frac{-7 - \sqrt{289}}{2} = -12$

Since the time to complete the job has to be a positive value.

Jennifer would complete the job on her own in 5 hours.

4 0

2 years ago

In a city, 60% of the residents live in houses and 40% of the residents live in apartments. Of the people who live in houses, 20

Step2247 [10]

75%; so if we say there are 100 people in this city that means 60 of them live in houses and 40 of them live in apartments. Of the 60 living in houses 20% of them (12% of total population; 60 x .20) own their own business and those in apartments (40) 10% of them (4% of total pop.; 40 x .10) have their own business. In total 16 of the 100 people have businesses and 12 of those people live in houses so 12/16 equals .75. We multiply this by 100 to get the percent so there’s 75% that a person who owns a business in this city will also live in a house.

6 0

2 years ago