To which graph does the point (–1, –4) belong?
y < –x + 4
y < –x – 5
y < 2x – 3
y < 5x + 1
6 Answers
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Well, let's plug in the values we know for x and y to find out.
-4 <? -(-1) + 4
-4 <? 1 + 4
-4 <? 5
Yes. So the point is in this graph.
-4 <? -(-1) - 5
-4 <? 1 - 5
-4 <? -4
No. -4 is not less than itself. The point is outside this graph.
-4 <? 2(-1) - 3
-4 <? -2 - 3
-4 <? -5
No. -4 is not less than -5. The point is outside this graph.
-4 <? 5(-1) + 1
-4 <? -5 + 1
-4 <? -4
No. -4 is not less than itself. The point is outside this graph.
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(–1, –4) belongs to the graph of y < –x + 4 because (-4) < –(–1) + 4
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Y < -X + 4.
You put (-1) in for X & (-4) in for Y.
(-4) < -(-1) +4. -4 < 1 + 4. -4 < 5 is true.
(-4) < -(-1) - 5. -4 < 1 - 5. -4 < -4 is false.
-(4) < 2(-1) - 3. -4 < -2 -3. -4 < -5 is false.
(-4) < 5(-1) + 1. -4 < -5 + 1. -4 < -4 is false.
Source(s): Mah Braynz. (And a Graphing Calculator helps, too.) -
1. put x = -4, and y= -1 in each inequality.
1st case y < -x + 4
=> -4 < -(-1) + 4
=> -4 < 1+5
=> -4 < 6 this is true.
but it is not true for rest of the cases,
Hence answer is y < -x + 4 .
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-4 <-(-1)+4
-4 < 1+4
-4 < 5
it belongs to this one since it comes out being correct
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Substituting the values for x and y
1] y < -x + 4
-4 < 1 + 4........................this is true