What is the slope of the line passing through (7,9) ;(-6,7) (7,9);(6,7)?

1 Answer
Sep 19, 2016

2/13213

Explanation:

Slope (gradient) is the change in the y-axis compered to the appropriate change in the x-axis.

Slope" "-> ("change in y")/("change in x") change in ychange in x reading left to right on the graph.

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Consider the order given in the question

Let point 1 be " "P_1->(x_1,y_1)=(7,9) P1(x1,y1)=(7,9)

Let point 2 be " "P_2->(x_2,y_2)=(-6,7) P2(x2,y2)=(6,7)

color(green)("But "x_2" is less than "x_1 ")But x2 is less than x1
color(green)("and we should read left to right ( using "x")")and we should read left to right ( using x)

x_1 larr---------x_2 x1x2
color(red)(uarr)" direction of reading is wrong" color(red)(uarr) direction of reading is wrong
color(red)("Highest value lowest value ")Highest value lowest value

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Change the order given in the question:

Rewrite as:

Let point 1 be " "P_1->(x_1,y_1)=(-6,7) P1(x1,y1)=(6,7)

Let point 2 be " "P_2->(x_2,y_2)=(7,9) P2(x2,y2)=(7,9)

Slope" "-> ("change in y")/("change in x") =(y_2-y_1)/(x_2-x_1) =(9-7)/(7-(-6)) change in ychange in x=y2y1x2x1=977(6)

Slope =2/13 =213

Positive slope means that the graph line is going upwards as you read left to right.

Note that negative slope is downwards.

Tony B