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write the equation in point slope and slope intercept form of a line that passes through the given point (-3, -4), and has the given slope m = -1/2

User Justin Erswell
by
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1 Answer

19 votes
19 votes

Question 1.

Given the point:

(-3, -4)

Slope, m = - 1/2

Let's write the equation of the line that passes through the given point with the slope in point-slope form and slope intercept form.

• Point slope form:

Apply the point-slope equation:


y-y_1=m(x-x_1)

Now substitute -1/2 for m, then input (-3, -4) for x1 and y1 in the equation above.


\begin{gathered} y-(-4)=-(1)/(2)(x-(-3)) \\ \\ y+4=-(1)/(2)(x+3) \end{gathered}

Therefore, the equation in point slope form is:


y+4=-(1)/(2)(x+3)

• SLope intercept form:

Apply the slope intercept form of a linear equation:


y=mx+b

Where m is the slope and b is the y-intercept.

Substitute the following:

-1/2 for m

(-3, -4) for (x, y)

Then solve for b.


\begin{gathered} -4=-(1)/(2)(-3)+b \\ \\ -4=(3)/(2)+b \\ \\ \end{gathered}

Subtract 3/2 from both sides:


\begin{gathered} -4-(3)/(2)=(3)/(2)-(3)/(2)+b \\ \\ -(4)/(1)-(3)/(2)=b \\ \\ (-8-3)/(2)=b \\ \\ -(11)/(2)=b \\ \\ b=-(11)/(2) \end{gathered}

Therefore, the slope intercept form of the line is:


y=-(1)/(2)x-(11)/(2)

ANSWER:

Point-slope form:


y+4=-(1)/(2)(x+3)

Slope intercept form:


y=-(1)/(2)x-(11)/(2)

User Derek Fan
by
3.0k points
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