4
Consider the line y=-
Consider the line y= -4/9x+3
Find the equation of the line that is parallel to this line and passes through the point (9, 4).
Find the equation of the line that is perpendicular to this line and passes through the point (9, 4).

Respuesta :

Step-by-step explanation:

y = (-4/9)x + 3

-4/9 is the slope of the line. the factor is x is the slope in every line equation. the slope is always the ratio y/x.

the parallel line must have the same slope, of course.

but the y-intercept will be different.

so, its line equation looks like

y = (-4/9)x + c

we use the provided point coordinates to calculate this c.

4 = (-4/9)×9 + c

4 = -4 + c

c = 8

therefore, the parallel line equation is

y = (-4/9) + 8

a perpendicular line is a line that intercepts the original line by an angle of 90 degrees.

that means that its slope switches the original x and y, and also flips the sign.

the perpendicular slope is therefore : 9/4

so, the line equation looks like

y = (9/4)x + c

again, we use the provided point coordinates to calculate c :

4 = (9/4)×9 + c

4 = 81/4 + c

16/4 = 81/4 + c

-65/4 = c

the perpendicular line equation is

y = (9/4)x - 65/4