198k views
2 votes
Find the equation of the line with slope =-7 and passing through (-4,-5) .write your equation in point slope and slope intercept forms

1 Answer

5 votes

Point-slope form:

y - y₁ = m(x - x₁) "m" is the slope


You know:

m = -7

(-4 , -5) = (x₁ , y₁)

Plug these into the equation:

y - y₁ = m(x - x₁)

y - (-5) = -7(x - (-4))

y + 5 = -7(x + 4)



Slope-intercept form:

y = mx + b "m" is the slope, "b" is the y-intercept (the y value when x = 0)


You can solve this two ways:


#1: Since you know m = -7, plug it into the equation

y = mx + b

y = -7x + b

To find "b", plug in the point (-4, -5) into the equation

y = -7x + b

-5 = -7(-4) + b

-5 = 28 + b Subtract 28 on both sides

-33 = b


y = -7x - 33



#2: Use the point-slope form and change it to slope-intercept form by isolating/getting "y" by itself.

y + 5 = -7(x + 4) First distribute/multiply -7 into (x + 4)

y + 5 = -7x - 28 Subtract 5 on both sides

y = -7x - 33

User Jeremy Holt
by
8.1k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories