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3 years ago

Solve this system of equations: 5x + y = 7 20x + 2 = y

Mathematics

1 answer:

xz_007 [3.2K]3 years ago

7 0

Answer:

x = 1/5, y = 6

Step-by-step explanation:

5x + y = 7

y = 7 - 5x

Set equations equal to each other to eliminate y

7 - 5x = 20x + 2

7 = 25x + 2

5 = 25x

x = 1/5

y = 7 - 5(1/5)

y = 7 - 1

y = 6

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3 years ago

Find the equation of the line using the point-slope formula. Write the final equation using slope-intercept form. Perpendicular

polet [3.4K]

Answer:

<u>Slope-intercept form</u>: y = -5x - 8

<u>Point-slope form</u>: y - 2 = -5(x + 2)

Step-by-step explanation:

Given the equation, 5y = x - 4, which passes through point (-2, 2):

Transform the given equation into its <u>slope-intercept form</u>, y = mx + b.

In order to do so, divide both sides by 5 to isolate y:

5y = x - 4

$\displaystyle\mathsf{\frac{5y}{5}\:=\:\frac{1x\:-\:4}{5}}$

$\displaystyle\mathsf{y\:=\:\frac{1}{5}x\:-\:\frac{4}{5}}$ ⇒ This is the slope-intercept form of 5y = x - 4.

Next, we must determine the equation of the line that is perpendicular to $\displaystyle\mathsf{y\:=\:\frac{1}{5}x\:-\:\frac{4}{5}}$ .

<h2>Definition of Perpendicular Lines:</h2>

<u>Perpendicular lines</u> have <em>negative reciprocal</em> slopes. This means that if we multiply the slopes of two lines, their product will equal to -1.

In other words, if the slope of the given equation is m₁, and the slope of the other line perpendicular to the given linear equation is m₂, then: m₁ × m₂ = -1.

Slope of the given equation: m₁ = ⅕

$\displaystyle\mathsf{Slope\:of\:other\:line\:(m_2 )\:=\:-5\:or\:-\frac{5}{1}}$

If we multiply these two slopes:

m₁ × m₂ = -1

$\displaystyle\mathsf{m_1\:\times\\\:m_2\:=\:\frac{1}{5}\times\\-\frac{5}{1}\:=\:-1}$

Now that we have identified the slope of the other line that is perpendicular to 5y = x - 4, we must determine the y-intercept of the <u>other line</u>.

The <u>y-intercept</u> is the point on the graph where it crosses the y-axis, for which it is the value of "y" when its corresponding x-coordinate equals to zero (0).
Thus, the standard coordinates of the y-intercept is (0, <em>b</em>), for which its y-coordinate is the value of "<em>b</em>" in the slope-intercept form, y = mx + b.

Using the <u>slope</u> of the other line, m₂ = -5, and the given point, (-2, 2), substitute these values into the slope-intercept form to find the value of the y-intercept, <em>b</em>:

y = mx + b

2 = -5(-2) + b

2 = 10 + b

Subtract 10 from both sides to isolate b:

2 - 10 = 10 - 10 + b

-8 = b

The equation of the other line that is perpendicular to 5y = x - 4 is:

Linear Equation that is perpendicular to 5y = x - 4 in slope-intercept form:

<h2>Rewrite the Equation in Point-slope Form:</h2>

The <u>point-slope form</u> is: y - y₁ = m(x - x₁)

In order to rewrite y = -5x - 8 in its point-slope form, we must substitute the value of the given point, (-2, 2) into the point-slope form:

y - y₁ = m(x - x₁)