66.2k views
2 votes
What is an equation of the line that passes through the points (1, 3) and (7, -3)?

User Paradox
by
7.1k points

1 Answer

6 votes

Answer:

y = -x + 4

Explanation:

y = mx + b

You need the slope (m) and the y-intercept (b)

Slope

Change in y over the change in x

(1,3) (7,-3)

The y values are -3 and 3. You find the change by subtraction

-3 - 3 = -6

(1,3)(7, -3)

The x values are 7 and 1. You find the change by subtraction

7 - 1 = 6

You make a fraction by the change in y in the numerator and the change in x in the denominator.


(-6)/(6) = -1

The slope is -1

y-intercept

Use the slope you just found -1 and one of the points given. I am going to use (1,3), but either point will work.

y = 3 From the point given (1,3)

x = 1 From the point given (1,3)

m = -1

Substitute these all in and solve for b

y = mx + b

3 = (-1)(1)+ b

3 = -1 + b Add 1 to both sides

3 + 1 = -1 + 1 + b

4 = b

The y-intercept is 4.

y =mx + b

y = -x + 4

User Faraway
by
6.4k points