# Use the point slope form line equation y+4=-4(x-2).  what point does this line pass through. Rewrite this equation in slope-intercept form. What is the x-intercept of this line.

flbyrne | Certified Educator

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The slope of a line is defined as the change in y divided by the change in x:

Slope=`(Deltay)/(Deltax)`

Given a point `(x_1,y_1)`, the change in y can be written as

`Deltay=y-y_1`

And the change in x can be written as:

`Deltax=x-x_1`

The equation of the line can then be written:

`y-y_1=(Slope)(x-x_1)`

In `y-(-4)=-4(x-2)` the point `(x_1,y_1)` is equal to (2,-4) and the slope is equal to -4.

Therefore the line passes through the...

(The entire section contains 2 answers and 250 words.)

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justaguide | Certified Educator

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tonys538 | Student

The equation of a line through (a,b) with slope m is given by (y - b)/(x - a) = m

The equation of the line that is given can be rewritten in this form.

y + 4 = -4*(x - 2)

(y + 4)/(x - 2) = -4

This line passes through the point (2, -4).

In slope intercept form this line has an equation of the form y = mx + c

y + 4 = -4*(x -2 )

y + 4 = -4x + 8

y = -4x + 4

At the x-intercept, the y-coordinate is 0.

0+ 4 = -4*x + 8

-4*x = -4

x = 1

The x-intercept is 1.

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Wiggin42 | Student

y+4=-4(x-2)

Recall the point slope formula:

y - y1 = m(x - x1) where m is the slope and (x1,y1) is a point.

Realize that y1 = -4 and x1 = 2 so a point that this line goes through is (2, -4)

To get this into slope intercept, just distribute the -4 and solve for y like this:

y + 4 = -4x + 8

y + -4x + 8 - 4

y = -4x + 4    Done!

The x-intercept means the y value is 0 so plug that in and solve for x:

0 = -4x + 4

x = -4/-4 = 1

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