All categories

3 years ago

What is the value of x when -3x + 7x = -12?

Mathematics

2 answers:

Nonamiya [84]3 years ago

6 0

-3x + 7x = -12

(-3 + 7)x = -12

4x = -12 (divide 4 from each side)

4x/4 = -12/4

x = -12/4

x = 3 <-answer

Natalka [10]3 years ago

4 0

-3 + 7x = -12

First, simplify -3x + 7x to get 4x. / Your problem should look like: 4x = -12
Second, divide both sides by 4. / Your problem should look like: x = $- \frac{12}{4}$
Third, simplify $\frac{12}{4}$ to 3. / Your problem should look like: x = -3

Answer: x = -3

You might be interested in

An angle's supplement is nine times of its complementary angle. Find the measure of the angle, the complement of the angle,and t

Nezavi [6.7K]

S = 9C
first sentence written as an expression
Where S represents the angles supplement
and C represents the angles complement
A + S = 180
definition of supplementary allows me to make this statement Where A is the original angle
A + C = 90
definition of complimentary allows this statement
now add the prior 2 statements together
A + S + A + C = 180 + 90
now simplify
2A + S + C = 270
now replace S with 9C using first statement
2A + 9C + C = 270
now simplify
2A + 10C = 270
now divide both sides by 2
A + 5C = 135
now using the second statement isolate A by adding C to both sides
A = 90 - C
now combine the two prior statements
90 - C + 5C = 135
now simplify
90 + 4C = 135
now subtract 90 from both sides
4C = 45
now divide both sides by 4
C = 11.25
so the complimentary angle is 11.25
now take the third equation and substitute in C
A + 11.25 = 90
now subtract 11.25 from both sides
A = 78.75
so the original angle is 78.75
now use the second equation and substitute in A
78.75 + S = 180
now subtract 78.75 from both sides
S = 101.25
so the suplimentary angle is 101.25

7 0

3 years ago

Use the conversions given below to change 83 kg into stones.

eduard

83 kg converted to stones is 13 stones.

Step-by-step explanation:

Given,

We have to convert 83 kg to stones.

As it is given,

1 kg = 2.2 pounds

83 kg = 2.2*83 pounds

83 kg = 182.6 pounds

Now,

14 pounds = 1 stone

1 pound = $\frac{1}{14}\ stones$

182.6 pounds = $\frac{1}{14}*182.6$

182.6 pounds = 13.04 stones

Rounding to one dp

182.6 pounds = 13.0 stones

83 kg converted to stones is 13 stones.

Keywords: converting units, division

Learn more about division at:

#LearnwithBrainly

4 0

2 years ago

The manager of a pizza chain in Albuquerque, New Mexico, wants to determine the average size of their advertised 16-inch pizzas.

erastova [34]

Answer:

n=50

Step-by-step explanation:

1) Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X=16.10$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=1.8 represent the sample standard deviation

n=25 represent the sample size

2) Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

We need to find the degrees of freedom given by:

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

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=\pm 1.96$

Since we assume that we are taking a bigger sample then we can replace the t distribution with the normal standard distribution, and we can assume that th population deviation is 1.8. The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)