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The given line passes through the points (0,3) and (-4,0).what are 4 equations that describes this line?

User Roddy R
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1 Answer

21 votes
21 votes

We have a line that passes through point (0,3) and (-4,0).

Slope-intercept form:

We can calculate the slope of the line as:


m=(\Delta y)/(\Delta x)=(y_2-y_1)/(x_2-x_1)=(0-3)/(-4-0)=(-3)/(-4)=(3)/(4)

The y-intercept can now be calculated using the slope and one of the points:


\begin{gathered} y=mx+b \\ 3=(3)/(4)\cdot0+b=0+b=b \\ b=3 \end{gathered}

Then, we can express the equation as:


y=(3)/(4)x+3

Direct variation:

We can not express as a direct variation line as the line do not go through the origin.

Point-slope form:

This form is:


y-y_1=m(x-x_1)

We have to know the slope and one point in order to be able to write it.

The slope is 3/4 and one of the points is (0,3). We can write it as:


y-3=(3)/(4)(x-0)

Two intercept form:

This form is:


ax+by=c

We can write this for our case as:

When x=0, y=c/b=3, and when y=0, x=c/a=-4.

We can write that c=1, and then b=1/3 and a=-1/4.

Then, our equation becomes:


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

If we multiply both sides by 12 (the common factor of 3 and 4), we would get:


-3x+4y=12

that is equivalent to the previous equation.

User H S
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