# How do you graph y= x - 3?

May 10, 2016

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#### Explanation:

In straight line graphs it is better to determine 3 points as the third point acts as a check. They should all line up.

Determine point 1$\to {P}_{1} \to \left({x}_{1} , {y}_{1}\right)$

Let $x = 0$ giving $y = 0 - 3 \implies y = - 3$

So $\textcolor{b l u e}{{P}_{1} \to \left({x}_{1} , {y}_{1}\right) \to \left(0 , - 3\right)}$
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Determine point 2$\to {P}_{2} \to \left({x}_{2} , {y}_{2}\right)$

Let $y = 0$ giving $0 = x - 3$

$\implies 0 + 3 = x - 3 + 3$

But -3+3=0

$x = 3$

So color(blue)(P_2->(x_2,y_2)->(3,0)#
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Determine checking point 3$\to {P}_{3} \to \left({x}_{3} , {y}_{3}\right)$

I chose an $x$ value of 5 giving

$y = 5 - 3 = + 2$

So $\textcolor{b l u e}{{P}_{3} \to \left({x}_{3} , {y}_{3}\right) \to \left(5 , 2\right)}$
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Mark the points and draw a straight line through extending it to the edge of the squared area on the paper.

$\textcolor{b r o w n}{\text{Don't forget to label your points and write a title to your graph}}$
$\textcolor{b r o w n}{\text{For example: Graph of "y=x-3" This gets you extra marks.}}$
$\textcolor{b r o w n}{\text{You must label your axis as well!}}$ 