Answer:
Step-by-step explanation:
The slope-intercept form of an equation of a line:
[tex]y=mx+b[/tex]
m - slope
b - y-intercept
The formula of a slope:
[tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
We have the points (1, 4) and (-1, -4).
Substitute:
[tex]m=\dfrac{-4-4}{-1-1}=\dfrac{-8}{-2}=4[/tex]
Put it and the coordinates of the point (1, 4) to the equation of a line:
[tex]4=4(1)+b[/tex]
[tex]4=4+b[/tex] subtract 4 from both sides
[tex]0=b\to b=0[/tex]
Finally we have:
[tex]y=4x[/tex]
