I graphed a line?

2016-05-25 3:08 am

I graphed this inequality 2x + 3y <or= 18 using the x and y intercept with a test point of (0,0). Test point comes out to be 36 <or= 18. This inequality is not true so according to the test point you shade above the line where (0,0) is not included. However in the correct answer, below the line is shaded. SOMEONE EXPLAIN!!!

回答 (1)

用戶48836

2016-05-25 3:48 am

✔ 最佳答案

2x + 3y ≤ 18
3y ≤ -2x + 18
y ≤ -2/3 x + 6

The y intercept for the line is 6 (0,6).
(0,0) is below (0,6).

2x + 3y ≤ 18
2(0)+3(0) = 0 ≤ 18. This is true.

y ≤ -2/3,x + 6
0 ≤ -2/3(0) + 6
0 ≤ 6
Again true so shade below. Also include the line because of ≤.

A test point helps for one equality however sometimes you know above or below from the direction of the inequality when solved for y.

A test point helps more when dealing wiling multiple inequalities as do arise in linear programming problems.

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