Question

What is the slope of the line shown in the graph below?

a)

2


b)

5


c)

-1/2


d)

-2

Answer 1

Equation: m = y2-y1/x2-x1
Pick (x1, y1) = (2,1) and (x2, y2) = (0,5)
m = (5-1)/(0-2)
m = 4/(-2)
m = -2

So answer is d

Answer 2

Answer:

D) -2

You want to know the angular coefficient of the line shown in the graph.

The slope is usually given by this formula:

$m = \frac{Δy}{Δx}$

Your case is quite easy. I usually do this by taking any 2 consecutive points of the grid intersected by the line, making a simple right triangle and then using that formula.

You can take for example the 2 points: (2,1) and (1,3).

The other point you need to make a right triangle would be (1,1).

Now calculate

$m = \frac{Δy}{Δx}$

Δy is equal to 2. Δx is equal to -1. Then m is equal to -2.

If you're wondering why the Δx is negative... When the angle between the line and the positive side of the x axis is greater than 90 degrees, just like in your case, the slope is negative.

If you do the maths correctly and calculate the Δx correctly, you will find out that it's negative.