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krek1111 [17]
3 years ago
14

Follow the directions to solve the system of equations by elimination. 8x + 7y=39 4x – 14y = -68​

Mathematics
1 answer:
harina [27]3 years ago
8 0

Step-by-step explanation:

Hey there!

Here;

The equations are;

8x + 7y = 39.......(i)

4x - 14y =  - 68..........(ii)

Multiplying equation (i) by 2.

16x + 14y = 78

<u>4</u><u>x</u><u> </u><u>-</u><u> </u><u>1</u><u>4</u><u>y</u><u> </u><u> </u><u> </u><u>=</u><u> </u><u>-68</u>

20x = 10

x =  \frac{10}{20}

x = 1/2.

Putting value of 'x' in equation (i).

8 \times  \frac{1}{2}  + 7y =  39

4 + 7y = 39

7y = 3 9 - 4

y =  \frac{35}{7}

Therefore the value of y is 5.

<u>Check</u><u>:</u>

<u>Put</u><u> </u><u>value</u><u> </u><u>of</u><u> </u><u>x</u><u> </u><u>and</u><u> </u><u>y</u><u> </u><u>in</u><u> </u><u>equation</u><u> </u><u>(</u><u>i</u><u>)</u><u>.</u>

8x + 7y = 39

8 \times  \frac{1}{2}  + 7 \times 5 = 39

4 + 35 = 39

39 = 39

(True).

<u>Therefore</u><u>, </u><u>the</u><u> </u><u>solution</u><u> </u><u>is</u><u> </u><u>;</u><u> </u><u>(</u><u>1</u><u>/</u><u>2</u><u>,</u><u>5</u><u>)</u><u>.</u>

<em><u>Hope it helps</u></em><em><u>.</u></em><em><u>.</u></em><em><u>.</u></em>

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Rounding<br>Round each number to the nearest hundred<br>7892<br>472​
mixas84 [53]

Answer:

7892 = 7900

472 = 500

Step-by-step explanation:

4 0
3 years ago
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A given line has the equation 10x + 2y = −2.
worty [1.4K]

The equation is \boxed{ \ y = - 5x + 12 \ or \ y = 12 - 5x} \ }

<h3>Further explanation </h3>

This case asking the end result in the form of a slope-intercept.

<u>Step-1: find out the gradient. </u>

10x + 2y = -2

We isolate the y variable on the left side. Subtract both sides by 10x, we get:

2y = - 10x - 2  

Divide both sides by two

y = -5x -1

The slope-intercept form is \boxed{ \ y = mx + c \ }, with the coefficient m as a gradient. Therefore, the gradient is m = -5.

If you want a shortcut to find a gradient from the standard form, implement this:  

\boxed{ \ ax + by = k \rightarrow m = - \frac{a}{b} \ }

10x + 2y = −2 ⇒ a = 10, b = 2

\boxed{m = - \frac{10}{2} \rightarrow m = -5}

<u>Step-2:</u> the conditions of the two parallel lines

The gradient of parallel lines is the same \boxed{ \ m_1 = m_2 \ }. So \boxed{m_1 = m_2 = -5}.

<u>Final step:</u> figure out the equation, in slope-intercept form, of the parallel line to the given line and passes through the point (0, 12)

We use the point-slope form.

\boxed{ \ \boxed{ \ y - y_1 = m(x - x_1)} \ }

Given that

  • m = -5
  • (x₁, y₁) = (0, 12)  

y - 12 = - 5(x - 0)

y - 12 = - 5x

After adding both sides by 12, the results is \boxed{ \ y = - 5x + 12 \ or \ y = 12 - 5x} \ }

<u>Alternative steps </u>

Substitutes m = -5 and (0, 12) to slope-intercept form \boxed{ \ y = mx + c \ }

12 = -5(0) + c

Constant c is 12 then arrange the slope-intercept form.

Similar results as above, i.e. \boxed{ \ y = - 5x + 12 \ or \ y = 12 - 5x} \ }

<u>Note: </u>

\boxed{Standard \ form: ax + by = c, with \ a > 0}

\boxed{Point-slope \ form: y - y_1 = m(x - x_1)}

\boxed{Slope-intercept \ form: y = mx + k}

<h3>Learn more </h3>
  1. A similar problem brainly.com/question/10704388
  2. Investigate the relationship between two lines brainly.com/question/3238013
  3. Write the line equation from the graph brainly.com/question/2564656

Keywords: given line, the equation, slope-intercept form, standard form, point-slope, gradien, parallel, perpendicular, passes, through the point, constant

7 0
3 years ago
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The product of my number and twice my number is 98.What is half my number how you solved the problem
fomenos
Product means multiply. I will be representing your number with x

x * 2(x) = 98
2x^2 = 98
x^2 = 49
x = 7
your number is 7. half of your number is 3.5
3 0
3 years ago
4. Solve the following system of equations for x.
Ber [7]

We are given the system of equations -:

\large{ \begin{cases} 2x + 3y =  - 14 \\ y = 6x + 22 \end{cases}}

Since the second equation is y-isolated equation. It can be substituted as y = 6x+22 in the first equation.

\large{2x + 3(6x + 22) =  - 14}

Expand 3 in the expression so we can combine like terms and isolate x-variable.

\large{2x + 18x + 66 =  - 14}

Then combine like terms.

\large{20x + 66 =  - 14}

Get rid of 66 from the left side by subtracting both sides by itself.

\large{20x + 66 - 66 =  - 14 - 66} \\  \large{20x =  - 80}

To finally isolate the variable, divide both sides by 20 so we can leave x only on the left side.

\large{ \frac{20x}{20}  =  \frac{ - 80}{20} }

Simplify to the simplest form.

\large{x =  - 4}

Normally, we have to find the y-value too but since we only find x-value. The answer is x = -4.

Answer

  • x = -4

I hope this helps! If you have any questions or doubts regarding my answer, explanation or system of equations, feel free to ask!

5 0
3 years ago
Am i right 5TH GRADE MATH THANKS!​
Genrish500 [490]

Answer:

Step-by-step explanation:

the answer is 7.9

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3 years ago
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