Question

Find the equation of the line that contains the given point and the given slope. Write the equation in slope-intercept form.

Answer 1

The slope-point form of a line:

$y-y_0=m(x-x_0)$

The slope-intercept form of a line:

$y=mx+b$

1.

$m=6,\ (4,\ 1)\to x_0=4,\ y_0=1$

Substitute

$y-1=6(x-4)\qquad|\text{use distributive property}\\\\y-1=6x-24\qquad|\text{add 1 to both sides}\\\\\boxed{y=6x-23}$

2.

$m=-5,\ (6,\ -3)$

Substitute

$y-(-3)=-5(x-6)\qquad|\text{use distributive property}\\\\y+3=-5x+30\qquad|\text{subtract 5 from both sides}\\\\\boxed{y=-5x+24}$

3.

$m=-\dfrac{1}{2},\ (-8,\ 2)\\\\y-2=-\dfrac{1}{2}(x-(-8))\\\\y-2=-\dfrac{1}{2}(x+8)\\\\y-2=-\dfrac{1}{2}x-4\qquad|\text{add 2 to both sides}\\\\\boxed{y=-\dfrac{1}{2}x-2}$

4.

$m=0,\ (-7,\ -1)\\\\y-(-1)=0(x-(-7))\\\\y+1=0\qquad|\text{subtract 1 from both sides}\\\\\boxed{y=-1}$