what would be the y intercept of a line that passes through the points (1,2) and (3,-8)

Answer 1

Hi Mya,

to determine what the y intercept is when the line crosses the y axis and x = 0, we first have to determine the equation of the line. We are given two points, we can determine the slope and then put one of the ordered pairs into the y = m x + b.

slope is the difference of the two y's divided by the difference of the two x values. 2 --8 for the y is 10 and 1-3 is -2. So 10 / -2 = -5.

Then take one of the ordered pairs and substitute it into y = m x +b and solve for b the y intercept.

b = 7

I hope this helps

Answer 2

The line passes through (1,2) and (3,-8)

the equation of the line passing through 2 points are

(x-x1)/(x2-x1) = (y-y1)/(y2-y1)

(x-1)/(3-1) = (y-2)/(-8-2)

(x-1)/2 = (y-2)/-10

y-2 = -5x + 5

y = -5x + 7

which is the equation of the form y = mx + c, where c is the y-intercept

SO the y-intercept of the line is 7.

Answer 3

First, you need to find the slope of the line. Use the equation

(y₂ - y₁)/(x₂ - x₁) to find the slope. This would be (-8-2)/(3-1) = -10/2 = -5

So the slope is -5.

Next, use the equation y = mx + b to find the intercept. We know the slope, and you can use either of the two points for x and y. Plug in like this

2 = (-5)(1) + b

b = 7

So the y intercept is 7!

The line would be y = -5x +7