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a. Is (3,9) a solution to y<16−x ? b. Is (4,11) a solution to y≤14−x ? c. Is (5,10) a solution to y>15−x ? d. Is (6,15) a solution to y≥16−x ?

1 Answer

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Step-by-step explanation:

Let the point (x,y) = (3,9) and the inequality y<16−x. If the point (x,y) is a solution to this inequality then replacing the coordinates of the point (x,y) on the inequality, the inequality would be true. Let's check this:


9<16−3

this is equivalent to saying:


9<13

this is true, thus (3,9) is a solution to y<16−x.

Similarly consider the point (4,11) and the inequality y≤14−x. Thus:


11≤14−4

this is equivalent to:


11≤10

this is a contradiction, so we can conclude that the point (4,11) is not a solution to y≤14−x.

Now, consider the point (5,10) and the inequality y>15−x. Then:


10>15−5

this is equivalent to:


10>10

this is a contradiction, so we can conclude that the point (5,10) is not a solution to y>15−x.

Finally, consider the point (6,15) and the inequality y≥16−x. Then:


15≥16−6

this is equivalent to:


15≥10

this is true, thus (6,15) is a solution to y≥16−x.

We can conclude that the correct answer is:

Answer:

a) (3,9) is a solution to y<16−x.

b) (4,11) is not a solution to y≤14−x.

c) (5,10) is not a solution to y>15−x.

d) (6,15) is a solution to y≥16−x.

User Med Abida
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