All categories

3 years ago

Solve using elimination: 3x + 2y = -13 and 3x + 4y = 1

Mathematics

2 answers:

artcher [175]3 years ago

7 0

So first we subtract the 2nd row from the 1st row

-2y=-14

We divide each side by -2 and leaves us with y=7.

Now we substitute y=7 into any of the two equations above.

Well I chose 3x+2y=-13

3x+2(7)=-13

3x+14=-13

Subtract 14 form both sides and leaves us with 3x=27

Now we divide each side by 3 and leaves us with 9

So the answer is (x,y)=(7,9)

Hope this helps :^)

Nady [450]3 years ago

3 0

Let’s put the second equation on top

3x + 4y = 1
-3x + 2y = -13

I’m subtracting the first eqautionfrom the second

2y = 14
Y= 7
Plug in 7 for y in either of the original equations

3x + 28 = 1
3x = -27
X= -9

The answer is (-9,7)

You might be interested in

One number is larger than another by 9. If the greater number is increased by 10, and the lesser number is tripled, the sum of t

kkurt [141]

Answer:

The larger number is -6, the smaller number is -15

Step-by-step explanation:

We have two numbers, a and b.

We know that one number is larger than another by 9.

Then we can write:

a = b + 9

then a is larger than b by 9 units.

If the greater number is increased by 10 (a + 10) and the lesser number is tripled (3*b), the sum of the two would be -41:

(a + 10) + 3*b = -41

So we got two equations:

a = b + 9

(a + 10) + 3*b = -41

This is a system of equations.

One way to solve this is first isolate one variable in one of the two equations:

But we can see that the variable "a" is already isolated in the first equation, so we have:

a = b + 9

now we can replace that in the other equation:

(a + 10) + 3*b = -41

(b + 9) + 10 + 3*b = -41

now we can solve this for b.

9 + b + 10 + 3b = -41

(9 + 10) + (3b + b) = -41

19 + 4b = -41

4b = -41 -19 = -60

b = -60/4 = -15

b = -15

then:

a = b + 9

a = -15 + 9 = -6

a = -6

7 0

2 years ago

if a circular rug has a radius of 1 yard. what is the area of the rug to the nearest tenth of a square foot

Alecsey [184]

28.26 feet squared if using 3.14 for pi

4 0

3 years ago

A light flashes every 1 minute 15 seconds. another flashes every 1 minute 40 seconds. suppose they flash together at certain tim

ASHA 777 [7]

Answer:

5 minutes

Step-by-step explanation:

To get the response to this question, it would be required to convert both times to seconds alone.

For the first, the time It takes to flash is 1 minute 15 seconds which is same as 75 seconds

For the second, it takes 1 minute 40 seconds which is same as 100 seconds.

Now to get the time they would flash together, we need to know their lowest common multiples. The values involved are 75 and 100. Thus, the lowest common multiple of both is 300.

This is equivalent to 300 seconds which is 5 minutes time

6 0

3 years ago

Read 2 more answers

Solve and find the integer of 4x^2-19x-5

Anarel [89]

(x-5)(4x+1)
4x^2 times -5 is -20 the factors of -20 are -1x20, 1x-20... but to make the -19x you would add together the 1 and -20 because 1-20 is -19.
This then splits off to factorise 4x^2-20x, making this side 4x(1x-5) carry the brackets over to make it 1(1x-5) joining the brackets together to make (4x+1)(x-5)

5 0

3 years ago

If 65 percent of the population of a large community is in favor of a proposed rise in school taxes, approximate the probability

xz_007 [3.2K]

Answer: a) 0.99917 b) 0.7054 c) 0.9820

Step-by-step explanation:

Let X denotes the number of people are in favor of a proposed rise in school taxes.

Era re given that p(probability that a person is in favor of a proposed rise )= 0.65

Sample size : n= 100

Mean= np = 100(0.65)=65

Standard deviation: $\sigma=\sqrt{np(1-p)}\\\\=\sqrt{100(0.65)(0.35)}\\\\=4.76969600708\approx4.77$

a) Now, the probability that a random sample of 100 people will contain at least 50 who are in favor of the proposition :

$P(x\geq50)=P(\dfrac{x-\mu}{\sigma}\geq\dfrac{50-65}{4.77})\\\\=P(z\geq-3.144)\\\\=P(z-z)=P(Z$

b) between 60 and 70 inclusive who are in favor;

$P(60$

c) fewer than 75 in favor.

$P(x$

3 0

3 years ago