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sergey [27]
3 years ago
11

4/x - 3/y = 1 ; 6/x + 15/y = 8 solve this equation​

Mathematics
1 answer:
Soloha48 [4]3 years ago
4 0

Answer:

x=2

y=3

Solution:

First we find common denominators. It is "xy". Then we multiply numerators by common denominator. We get followings:

(4y-3x)/xy=1; (6y+15x)/xy=8

Then

4y-3x=xy;

6y+15=8xy

Multiply first equasion by 5

20y-15x=5xy

Now we add two equasions to get one

20y-15x=5xy

6y+15x=8xy

We get

26y=13xy

Cut "y" and we will find "x"

26=13x

x=2

Put x value into the first equasion(4y-3x=xy) to find out "y"

4y-6=2y

2y=6

y=3

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Twice the difference of a number and 1 is 4 more than that number. find a number using polyas 4 steps
professor190 [17]

Answer:

x=3

Step-by-step explanation:

2(x-1)=4

2x-2=4

2x=4+2

2x=6

x=6/2=3

8 0
3 years ago
Please help!!<br> Write a matrix representing the system of equations
frozen [14]

Answer:

(4, -1, 3)

Step-by-step explanation:

We have the system of equations:

\left\{        \begin{array}{ll}            x+2y+z =5 \\    2x-y+2z=15\\3x+y-z=8        \end{array}    \right.

We can convert this to a matrix. In order to convert a triple system of equations to matrix, we can use the following format:

\begin{bmatrix}x_1& y_1& z_1&c_1\\x_2 & y_2 & z_2&c_2\\x_3&y_2&z_3&c_3 \end{bmatrix}

Importantly, make sure the coefficients of each variable align vertically, and that each equation aligns horizontally.

In order to solve this matrix and the system, we will have to convert this to the reduced row-echelon form, namely:

\begin{bmatrix}1 & 0& 0&x\\0 & 1 & 0&y\\0&0&1&z \end{bmatrix}

Where the (x, y, z) is our solution set.

Reducing:

With our system, we will have the following matrix:

\begin{bmatrix}1 & 2& 1&5\\2 & -1 & 2&15\\3&1&-1&8 \end{bmatrix}

What we should begin by doing is too see how we can change each row to the reduced-form.

Notice that R₁ and R₂ are rather similar. In fact, we can cancel out the 1s in R₂. To do so, we can add R₂ to -2(R₁). This gives us:

\begin{bmatrix}1 & 2& 1&5\\2+(-2) & -1+(-4) & 2+(-2)&15+(-10) \\3&1&-1&8 \end{bmatrix}\\\Rightarrow\begin{bmatrix}1 & 2& 1&5\\0 & -5 & 0&5 \\3&1&-1&8 \end{bmatrix}

Now, we can multiply R₂ by -1/5. This yields:

\begin{bmatrix}1 & 2& 1&5\\ -\frac{1}{5}(0) & -\frac{1}{5}(-5) & -\frac{1}{5}(0)& -\frac{1}{5}(5) \\3&1&-1&8 \end{bmatrix}\\\Rightarrow\begin{bmatrix}1 & 2& 1&5\\ 0 & 1 & 0& -1 \\3&1&-1&8 \end{bmatrix}

From here, we can eliminate the 3 in R₃ by adding it to -3(R₁). This yields:

\begin{bmatrix}1 & 2& 1&5\\ 0 & 1 & 0& -1 \\3+(-3)&1+(-6)&-1+(-3)&8+(-15) \end{bmatrix}\\\Rightarrow\begin{bmatrix}1 & 2& 1&5\\ 0 & 1 & 0& -1 \\0&-5&-4&-7 \end{bmatrix}

We can eliminate the -5 in R₃ by adding 5(R₂). This yields:

\begin{bmatrix}1 & 2& 1&5\\ 0 & 1 & 0& -1 \\0+(0)&-5+(5)&-4+(0)&-7+(-5) \end{bmatrix}\\\Rightarrow\begin{bmatrix}1 & 2& 1&5\\ 0 & 1 & 0& -1 \\0&0&-4&-12 \end{bmatrix}

We can now reduce R₃ by multiply it by -1/4:

\begin{bmatrix}1 & 2& 1&5\\ 0 & 1 & 0& -1 \\ -\frac{1}{4}(0)&-\frac{1}{4}(0)&-\frac{1}{4}(-4)&-\frac{1}{4}(-12) \end{bmatrix}\\\Rightarrow\begin{bmatrix}1 & 2& 1&5\\ 0 & 1 & 0& -1 \\0&0&1&3 \end{bmatrix}

Finally, we just have to reduce R₁. Let's eliminate the 2 first. We can do that by adding -2(R₂). So:

\begin{bmatrix}1+(0) & 2+(-2)& 1+(0)&5+(-(-2))\\ 0 & 1 & 0& -1 \\0&0&1&3 \end{bmatrix}\\\Rightarrow\begin{bmatrix}1 & 0& 1&7\\ 0 & 1 & 0& -1 \\0&0&1&3 \end{bmatrix}

And finally, we can eliminate the second 1 by adding -(R₃):

\begin{bmatrix}1 +(0)& 0+(0)& 1+(-1)&7+(-3)\\ 0 & 1 & 0& -1 \\0&0&1&3 \end{bmatrix}\\\Rightarrow\begin{bmatrix}1 & 0& 0&4\\ 0 & 1 & 0& -1 \\0&0&1&3 \end{bmatrix}

Therefore, our solution set is (4, -1, 3)

And we're done!

3 0
3 years ago
My sisters phone is dead and she needs to know his question so I'll just tell you it!...
Vanyuwa [196]
 I used a calculator and it said the answer is 430858661.

The only way I know how to do this sort of long sum is with a calculator....
All you need to do is input 43789 * 9 + 138 * 12 - 1345 + 124556 x 3456 - 1287 and you will get the answer. Converted the words into the numerical symbols like times to *

If you want it to be more readable add commas so it's 430,858,661. You do it every 3 numbers. 

You'll want to do it the right order of operations since not all calculators do this automatically and it's a good habit >_>, using an acronym like BIDMAS (using the brit acronym lol) is a good way to remember this (<span>Brackets, Indices, Division, Multiplication, Addition, Subtraction)

So you'll need to do the multiplication first and then the addition and then the subtraction so this is the correct order. You want to use the brackets so it does it in the right order. 
(43 789 * 9) + (138 * 12) - 1345 + (124 556 x 3456) - 1287</span>
5 0
3 years ago
Which line is the graph of y = x?
satela [25.4K]

B in has the intersection with quadrant 1 and 3

5 0
3 years ago
On a five-year loan of $2,000 with an interest rate of 5%, how much total interest will you pay?
iren2701 [21]

Answer:

40001/20

Step-by-step explanation:

might want to fact check it just in case.

7 0
3 years ago
Read 2 more answers
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