Question

Please helppppppppppp me so the problem its jessica said that the sum of −8+d is always positive when the value of d is greater than 0.
• Is jessica statement always true, sometimes true or never true? Explain your answer.
• Provide at least two examples that support your answer.

Answer 1

Answer: Sometimes true

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Explanation:

-8+d is positive only when d > 8

Here's why

-8+d > 0

-8+d+8 > 0+8 .... add 8 to both sides

d > 8

So if Jessica said "d is greater than 8", then her claim would always be correct.

However, her claim is sometimes true.

Two counter examples could be when d = 1 and d = 2.

If d = 1, then -8+d = -8+1 = -7 which isn't positive.

If d = 2, then -8+d = -8+2 = -6 which also isn't positive.

Basically if d is anything smaller than 8, then you'll have -8+d be negative.

If d is something larger than 8, say d = 9, then -8+d = -8+9 = 1 which is finally positive.