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What is the equation of a line that passes through the points (2,5) and (4,3)

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User Bxjx
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1 Answer

6 votes

Answer:

Point-Slope form:

y - 5 = -1(x - 2)

or, Slope-Intercept:

y = -x + 7

or, Standard form:

x + y = 7

Explanation:

In order to write the equation of a line in Point-Slope form you just need a point and the slope. You have two points so you can calculate the slope (and use either point)

For the slope, subtract the y's and put that on top of a fraction. 5 - 3 is 2, put it on top.

Subtract the x's and put that on the bottom of the fraction. 2 - 4 is -2, put that on the bottom of the fraction. 2/-2 is the slope; let's simplify it.

2/-2

= -1

The slope is -1.

Lets use Point-Slope formula, which is a fill-in-the-blank formula to write the equation of a line:

y - Y = m(x - X)

fill in either of your points for the X and Y, and fill in slope for m. Slope is -1 and X and Y can be (2,5)

y - Y = m(x -X)

y - 5 = -1(x - 2)

This is the equation of the line in Point-Slope form. Solve for y to change it to Slope-Intercept form.

y - 5 = -1(x - 2)

use distributive property

y - 5 = -x + 2

add 5 to both sides

y = -x + 7

This is the equation of the line in Slope-Intercept Form.

Standard Form is:

Ax + By = C

y = -x + 7

add x to both sides

x + y = 7

This is the equation in Standard Form.

answered
User Ashoka
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8.0k points

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