6. A line goes through these two points, (-4, -1) anti (-9,-5).A. Find an equation for this line in point slope form.B. Find the equation for this line in slope intercept form. Be sure to show your work.C. If the y-coordinate of a point on this line is 7, what is the x-coordinate of this point?

Respuesta :

A. In order to find the equation, first we need to find the slope

[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]

m is the slope

(-4, -1)=(x1,y1)

(-9,-5)=(x2,y2)

we substitute the values

[tex]m=\frac{-5+1}{-9+4}=\frac{-4}{-5}=\frac{4}{5}[/tex]

then we use the point-slope form

[tex]y-y_1=m(x-x_1)[/tex]

we substitute the values

[tex]y+1=\frac{4}{5}(x+4)[/tex]

B. in order to find the slope-intercept form we need to isolate the y

[tex]y=\frac{4}{5}x+\frac{11}{5}[/tex]

C. if the y coordinate is 7

[tex]7=\frac{4}{5}(x)+\frac{11}{5}[/tex]

then we isolate the x

[tex]\frac{4}{5}x=7-\frac{11}{5}[/tex][tex]\begin{gathered} \frac{4}{5}x=\frac{24}{5} \\ x=\frac{5\cdot24}{5\cdot4} \\ x=6 \end{gathered}[/tex]

the value of the x-coordinate is 6 when the y-coordinate is 7