Answer:
rise from left to right
Step-by-step explanation:
Linear equation: [tex]y=mx+b[/tex]
(where [tex]m[/tex] is the slope and [tex]b[/tex] is the y-intercept)
Positive slope: rise from left to right
[tex]m[/tex] is a positive number
[tex]\textsf{e.g.}\:y=\dfrac45x+4[/tex]
Negative slope: fall from left to right
[tex]m[/tex] is a negative number
[tex]\textsf{e.g.}\:y=-\dfrac45x+4[/tex]
Zero slope: horizontal line
[tex]m=0[/tex]
[tex]\textsf{e.g.}\:y=0x+\dfrac45\implies y=\dfrac45[/tex]
Therefore, a horizontal line is [tex]y = a[/tex] (where [tex]a[/tex] is some constant)
Infinite slope: vertical line
[tex]m= \infty[/tex]
[tex]\sf slope\: (m)=\dfrac{change\:in\:y}{change\:in\:x}[/tex]
There is no change in x-values for a vertical line, so:
[tex]\sf \implies slope=\dfrac{change\:in\:y}{0}=\infty[/tex]
We also usually call the slope of this line undefined.
Therefore, a vertical line is [tex]x = a[/tex] (where [tex]a[/tex] is some constant)
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Attached graph:
Positive slope: black line
Negative slope: blue line
Zero slope: green line
Infinite slope: red line
