1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
KIM [24]
3 years ago
6

If the following system of equations was written as a matrix equation in the form AX = C, and matrix A was expressed in the form

[a c b d] , find the value of a - b + c + d.
5x + 7y = 7
3x - 2y = 9

My main problem is understanding which numbers are a, b, c, and d.

Mathematics
1 answer:
FrozenT [24]3 years ago
6 0
That's what I came up with. Still not sure of my answer. 

You might be interested in
Write 54 + 63 as the product of the<br> GCF of 54 and 63 and another sum.
photoshop1234 [79]

Answer:

9(6+7)

Step-by-step explanation:

5 0
2 years ago
Trevor says the figure B is a scaled copy of figure 8 because figure B is three times larger than figure A
yanalaym [24]

Answer:

Hi b

Step-by-step explanation:

3 0
3 years ago
A bag contains 9 marbles: 3 are green, 2 are red, and 4 are blue. Bob chooses a marble at random, and without putting it back, c
kvasek [131]

Answer: 1/18

Step-by-step explanation:

9 total marbles

2 red

so the first time he picks it would be a 2/9 chance of the marble being red

the second time there would be 8 total marbles and 2 red, so it would be a 2/8 or 1/4 chance.

the probability is found by doing 2/9*1/4 which equals 2/36 or 1/18.

8 0
2 years ago
A ladder leans against a building that angle of elevation of the latter is 70° the top of the ladder is 25 feet from the ground.
VashaNatasha [74]

Answer:

a. 20.5

Step-by-step explanation:

because this will form a right triangle we can use tan (opposite over adjacent) so an equation we could set up would be tan(70)=25/x

therefore we can just solve the equation which would give us 20.45. so if we round it the answer would be a

3 0
2 years ago
Read 2 more answers
Suppose that the national average for the math portion of the College Board's SAT is 515. The College Board periodically rescale
nasty-shy [4]

Answer:

a) 16% of students have an SAT math score greater than 615.

b) 2.5% of students have an SAT math score greater than 715.

c) 34% of students have an SAT math score between 415 and 515.

d) Z = 1.05

e) Z = -1.10

Step-by-step explanation:

To solve this question, we have to understand the normal probability distribution and the empirical rule.

Normal probability distribution

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Empirical rule

The Empirical Rule states that, for a normally distributed random variable:

68% of the measures are within 1 standard deviation of the mean.

95% of the measures are within 2 standard deviation of the mean.

99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

\mu = 515, \sigma = 100

(a) What percentage of students have an SAT math score greater than 615?

615 is one standard deviation above the mean.

68% of the measures are within 1 standard deviation of the mean. The other 32% are more than 1 standard deviation from the mean. The normal probability distribution is symmetric. So of those 32%, 16% are more than 1 standard deviation above the mean and 16% more then 1 standard deviation below the mean.

So, 16% of students have an SAT math score greater than 615.

(b) What percentage of students have an SAT math score greater than 715?

715 is two standard deviations above the mean.

95% of the measures are within 2 standard deviations of the mean. The other 5% are more than 2 standard deviations from the mean. The normal probability distribution is symmetric. So of those 5%, 2.5% are more than 2 standard deviations above the mean and 2.5% more then 2 standard deviations below the mean.

So, 2.5% of students have an SAT math score greater than 715.

(c) What percentage of students have an SAT math score between 415 and 515?

415 is one standard deviation below the mean.

515 is the mean

68% of the measures are within 1 standard deviation of the mean. The normal probability distribution is symmetric, which means that of these 68%, 34% are within 1 standard deviation below the mean and the mean, and 34% are within the mean and 1 standard deviation above the mean.

So, 34% of students have an SAT math score between 415 and 515.

(d) What is the z-score for student with an SAT math score of 620?

We have that:

\mu = 515, \sigma = 100

This is Z when X = 620. So

Z = \frac{X - \mu}{\sigma}

Z = \frac{620 - 515}{100}

Z = 1.05

(e) What is the z-score for a student with an SAT math score of 405?

We have that:

\mu = 515, \sigma = 100

This is Z when X = 405. So

Z = \frac{X - \mu}{\sigma}

Z = \frac{405 - 515}{100}

Z = -1.10

3 0
3 years ago
Other questions:
  • Change your money from dollars to british pounds.you got 560 pounds for 800 dollars.how many pounds will you get for 300 dollars
    15·1 answer
  • Q #14 please help to solve
    15·1 answer
  • Last season two running backs on the steelers football team rushed or a combined total of 1550 yards. One rushed 4 times as many
    6·2 answers
  • The hospitality committee is ordering large sandwiches that each serve 8 people. If 125 fifth graders are coming to the picnic,
    7·1 answer
  • A rectangle that is 30 inches long by 10 inched wide can be divided into three equal squares.
    11·1 answer
  • a speedboat that costs $45,000 is depreciating at a rate of 20% per year. Find the value of the boat after 4 years.
    8·1 answer
  • Bob tells mark he has 3 kids, the product of their ages is 72, this is not enough info so he gives the sum of the ages then fina
    9·2 answers
  • 10 points for whoever can solve this for my brother
    9·2 answers
  • 9. Shawn wants to make the perimeter of the
    14·1 answer
  • WILL MARK BRAINLIEST!!!
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!