All categories

3 years ago

What two numbers multiply to -8 and add to -4

Mathematics

1 answer:

Ronch [10]3 years ago

7 0

Answer:

-2-2√3, -2+2√3

Step-by-step explanation:

Let x represent one of the numbers. Then the other number is -4-x. We want the product to be -8:

x(-4-x) = -8

-4x -x^2 = -8 . . . . . eliminate parentheses

x^2 +4x = 8 . . . . . . multiply by -1

x^2 +4x +4 = 12 . . . add 4 to complete the square

(x +2)^2 = 12

x +2 = ±√12 = ±2√3

x = -2±2√3

The two numbers are -2-2√3 ≈ -5.4641, and -2+2√3 ≈ 1.4641.

You might be interested in

A physicist examines 25 water samples for nitrate concentration. The mean nitrate concentration for the sample data is 0.165 cc/

xz_007 [3.2K]

Answer:

The 80% confidence interval for the the population mean nitrate concentration is (0.144, 0.186).

Critical value t=1.318

Step-by-step explanation:

We have to calculate a 80% confidence interval for the mean.

The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.

The sample mean is M=0.165.

The sample size is N=25.

When σ is not known, s divided by the square root of N is used as an estimate of σM:

$s_M=\dfrac{s}{\sqrt{N}}=\dfrac{0.078}{\sqrt{25}}=\dfrac{0.078}{5}=0.016$

The degrees of freedom for this sample size are:

$df=n-1=25-1=24$

The t-value for a 80% confidence interval and 24 degrees of freedom is t=1.318.

The margin of error (MOE) can be calculated as:

$MOE=t\cdot s_M=1.318 \cdot 0.016=0.021$

Then, the lower and upper bounds of the confidence interval are:

$LL=M-t \cdot s_M = 0.165-0.021=0.144\\\\UL=M+t \cdot s_M = 0.165+0.021=0.186$

The 80% confidence interval for the population mean nitrate concentration is (0.144, 0.186).

6 0

3 years ago

Mariana is making a large pot of pasta. She mixes together 5 pounds of pasta, 6 pounds of sauce, and

Blizzard [7]

Answer:

Step-by-step explanation:

3 0

2 years ago

Read 2 more answers

Consider the functions:

jolli1 [7]

The x and y axis so that’s why it’s true

5 0

3 years ago

Read 2 more answers

Seventh graders collected some gold sand on a class field trip.

satela [25.4K]

Answer:

Class 7A collected 4.8 ounces of pure gold.

Step-by-step explanation:

Key skills required are: Percentages, Multiplication

We only need the information about Class 7A. They collected 40 oz that contains 12% gold.
In other words, this means that 12% of that 40 oz gold sand is pure gold.

Here we have to do 12% x 40 to find the number of oz of pure gold. We first have to convert 12% into a decimal. Divide it by a 100 (or move the decimal point 2 places to the left) and you will get 0.12.

Do 0.12 x 40 and you will get 4.8

Therefore, there are 4.8 oz of pure gold in Class 7A's gold sand

3 0

2 years ago

If you have 18 questions how many do you need to get right to have 50 percent correct

MrRa [10]

You would need exactly 9 correct questions to get a 50%.

We can find this by multiplying the total number of questions by the percentage we are looking for.

18*50% = 9

5 0

2 years ago