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Is the point (20 13) on this line? Explain your reasoning.

User Philsch
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1 Answer

18 votes
18 votes

In order to determine if the point (20,13) is on the line, it is necessary to write the equation of the line.

The general form of a linear equation is:

y = mx + b

where b is the y-intercept and m is the slope. Y-intercept is the value of y when x = 0. You can observe in the graph that b = 3.

The slope m is conputed by using the following formula:


m=(y_2-y_1)/(x_2-x_1)

where (x1,y1) and (x2,y2) are two points of the line. Use the points (0,3) and (6,6), you can select any other two points. Replace these values into the formula for m:


m=(6-3)/(6-0)=(3)/(6)=(1)/(2)

Then, the equation of the line is:


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

Now, replace the value of x = 20 in the previous equation, if y = 13, then the point (20,13) in on the line:


\begin{gathered} y=(1)/(2)(20)+3 \\ y=10+3 \\ y=13 \end{gathered}

Hence, the point (20,13) is on the line

User Reed
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