Which is the correct slope-intercept equation for a line that passes through the points (1,-3) and (-3,17)

Respuesta :

Answer:

[tex]y=-5x+2[/tex]

Step-by-step explanation:

Hi there!

What we need to know:

  • Slope-intercept form: [tex]y=mx+b[/tex] where m is the slope and b is the y-intercept (the value of y when x is 0)

1) Determine the slope (m)

[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex] where two points that the line passes through are [tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex]

Plug in the given points (1,-3) and (-3,17)

[tex]=\frac{17-(-3)}{-3-1}\\=\frac{17+3}{-3-1}\\=\frac{20}{-4}\\=-5[/tex]

Therefore the slope of the line is -5. Plug this into [tex]y=mx+b[/tex]:

[tex]y=-5x+b[/tex]

2) Determine the y-intercept (b)

[tex]y=-5x+b[/tex]

Plug in one of the given points and solve for b

[tex]-3=-5(1)+b\\-3=-5+b[/tex]

Add 5 to both sides of the equation to isolate b

[tex]-3+5=-5+b+5\\2=b[/tex]

Therefore, the y-intercept of the equation is 2. Plug this back into [tex]y=-5x+b[/tex]:

[tex]y=-5x+2[/tex]

I hope this helps!