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Secondary 1 | Maths
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How is question (a) different from (b)? In (a), x Square is written as (-4)(-4) =16. Why can’t I write a Square as (-1)(-1) = 1?
Date Posted: 4 years ago
Views: 266
you are correct to write as (-1)(-1) = 1.
the answer on the lower left is worse!
when a = -1, (a square) should be a x a = (-1)x(-1) = 1.
to get the smallest value of (a square)-(b square),
you need the smallest possible (a square) minus the largest possible (b square).
the mistake (very common mistake!) is that
you assumed the smallest (a square) is at a= -1.
the smallest possible (a square) is actually 0, when a=0.
regardless of whether a is positive, zero or negative,
(a square) must be greater than, or equal to, 0.
so, the smallest possible (a square)-(b square)
= (0 square) - (9 square)
= 0 - 81 = -81.
the answer on the lower left is worse!
when a = -1, (a square) should be a x a = (-1)x(-1) = 1.
to get the smallest value of (a square)-(b square),
you need the smallest possible (a square) minus the largest possible (b square).
the mistake (very common mistake!) is that
you assumed the smallest (a square) is at a= -1.
the smallest possible (a square) is actually 0, when a=0.
regardless of whether a is positive, zero or negative,
(a square) must be greater than, or equal to, 0.
so, the smallest possible (a square)-(b square)
= (0 square) - (9 square)
= 0 - 81 = -81.
81
a is zero to be the smallest
a is zero to be the smallest
See 1 Answer
done
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error in your (b) working, take note :)
Date Posted:
4 years ago
Thank you!
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