Answer in fraction form is: y ≤ (1/2)x - 5 or [tex]y \le \frac{1}{2}x-5[/tex]
Answer in decimal form is: y ≤ 0.5x - 5
You only need to pick one answer format.
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Explanation:
The drawing is below.
Let's label the four given points as A,B,C,D
For now, let's focus on the boundary points A(-2, -6) and B(4, -3). A straight line in the form y = mx+b passes through these points. Compute the slope.
m = (y2-y1)/(x2-x1)
m = (-3 - (-6))/(4 - (-2))
m = (-3 + 6)/(4 + 2)
m = 3/6
m = 1/2
m = 0.5
Now let's use one of those (x,y) points along with that m value to find the y intercept b. I'll use the coordinates from point A.
y = mx+b
-6 = 0.5*(-2)+b
-6 = -1 + b
-6+1 = b
-5 = b
b = -5
The equation of the boundary line is y = 0.5x-5 which is the same as saying y = (1/2)x - 5 or [tex]y = \frac{1}{2}x-5[/tex]. We can refer to this as line AB.
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If you were to plot all four points (A,B,C,D) on the same xy grid, then you'd find that point D is on line AB. We're told that point D is a solution to the inequality, which must mean we are going to involve "or equal to" as part of the inequality sign. This will allow points on the boundary to be part of the solution set.
Notice how point C is below line AB. Since point C is also a solution, this means we go for "less than" to shade below the boundary. Overall, the sign we go for is "less than or equal to" or in short ≤
Therefore, the inequality is y ≤ 0.5x - 5
which is the same as writing y ≤ (1/2)x - 5 or [tex]y \le \frac{1}{2}x-5[/tex]
