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tatiyna
3 years ago
5

Solve the system by the elimination method. Check your work. 2a + 3b = 6 5a + 2b - 4 = 0

Mathematics
1 answer:
Lyrx [107]3 years ago
4 0
Solve the system by the elimination method.
2a + 3b = 6
5a + 2b - 4 = 0 

multiply thru the top equation by 2
Multiply thru the bottom equation by 3

4a + 6b = 12
15a+ 6b = 12

Subtract and solve for "a":
11a = 0
a = 0

Solve for "b" using 2a + 3b = 6
2*0 + 3b = 6
b = 2
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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
WILL GIVE BRAINLST <br><br> HAVE A GOOD DAY
Sedbober [7]
1st one 17/100 2nd one 0.25


Because 0.17 would be like 17% out of 100% so the fraction simplified is 17/100

2. Since the area of a square is length×length
But according to the question we are asked to find the length and the area is given so we will have to solve this
L×L= area
L^2=0.25
Square root both sides
L=√0.25
L=0.5
Therefore the length of the square is 0.5
6 0
3 years ago
Please help me with this question it is in the picture
alexdok [17]

Answer:

complementary angles

Step-by-step explanation:

The sum of the angles is 67+23 = 90

When angles sum together to 90, the are called complementary

5 0
3 years ago
Read 2 more answers
HELP <br><br>Determine whether the relation is a function<br><br> y=2w=2​
nexus9112 [7]

Answer:

Hi there!

I might be able to help you!

It is NOT a function.

<u>Determining whether a relation is a function on a graph is relatively easy by using the vertical line test. If a vertical line crosses the relation on the graph only once in all locations, the relation is a function. However, if a vertical line crosses the relation more than once, the relation is not a function</u>. <u>X = y2 would be a sideways parabola and therefore not a function.</u> Good test for function: Vertical Line test. If a vertical line passes through two points on the graph of a relation, it is <em>not </em>a function. A relation which is not a function. The x-intercept of a function is calculated by substituting the value of f(x) as zero. Similarly, the y-intercept of a function is calculated by substituting the value of x as zero. The slope of a linear function is calculated by rearranging the equation to its general form, f(x) = mx + c; where m is the slope.

A relation that is not a function

As we can see duplication in X-values with different y-values, then this relation is not a function.

A relation that is a function

As every value of X is different and is associated with only one value of y, this relation is a function.

Step-by-step explanation:

It's up there!

God bless you!

3 0
3 years ago
You deposit $200 in an account earning 3.5% simple interest how long will it take for the balance of the account to be $221
Rus_ich [418]

It takes 3 years for the balance of account to be $ 221

<em><u>Solution:</u></em>

From given information,

Principal = $ 200

Rate of interest = 3.5 %

Amount after "n" years = $ 221

To find: number of years

In simple Interest,

Simple interest = amount earned - principal

Simple interest = 221 - 200 = 21

Thus simple interest earned is $ 21

<em><u>The formula for simple interest is given as:</u></em>

simple\ interest = \frac{ p \times n \times r}{100}

Where,

p is the principal

n is the number of years

r is the rate of interest per annum

Substituting the given values in formula,

21 = \frac{200 \times n \times 3.5}{100}\\\\21 = 2n \times 3.5\\\\n = \frac{21}{7}\\\\n = 3

Thus it takes 3 years for the balance of account to be $ 221

7 0
3 years ago
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