3 Answers: Choice B, choice D, choice E.
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Explanation:
We'll plug x = -10 into each equation shown. If we get y = 4 as an output, then it is one of the answers.
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A)
y = -x^2 + 6
y = -(-10)^2 + 6
y = -100 + 6
y = -94
We don't get y = 4, so we cross choice A off the list.
The point (-10,4) is not on y = -x^2+6. Instead, the point (-10,-94) is.
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B)
y = (-1/2)*x - 1
y = (-1/2)*(-10) - 1
y = 5 - 1
y = 4
We can see that x = -10 leads to y = 4. The point (x,y) = (-10,4) is on the line. Choice B is one of the answers.
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C)
y = (-1/10)*x - 3
y = (-1/10)*(-10) - 3
y = 1 - 3
y = -2
Choice C is not one of the answers since we want y = 4 as an output. So we can cross choice C off the list.
The point (-10,-2) is on the line instead of (-10,4)
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D)
y = (1/10)x + 5
y = (1/10)*(-10) + 5
y = -1 + 5
y = 4
Choice D is one of the answers
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E)
y = (1/5)*x^2 - 16
y = (1/5)*(-10)^2 - 16
y = (1/5)*(100) - 16
y = 20 - 16
y = 4
Choice E is one of the answers
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An alternative method is to graph each equation and see if (-10,4) is on the curve or not. See the diagram below. Only choices B, D and E have (-10,4) on their respective curves.
