Kahwai's answer to Nancy's Secondary 2 Maths Singapore question.
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Using
The formula
Know that
The square in between can be cancelled
Redo the sum
It is not that difficult
The formula
Know that
The square in between can be cancelled
Redo the sum
It is not that difficult
Date Posted:
3 years ago
See the new one
-ab should be simplified to the following
i.e
-ab = - (25 + 10√5)^⅓ (25 - 10√5)^⅓
= - (25² - 10² x 5)^⅓
= - (125)^⅓
= -5
But a² and b² still have the exponentials.
i.e a² = (25 + 10√5)^⅔
b² = (25 - 10√5)^⅔
a² + b² will not simplify to (25² + (10√5)²) x 2,
i.e
-ab = - (25 + 10√5)^⅓ (25 - 10√5)^⅓
= - (25² - 10² x 5)^⅓
= - (125)^⅓
= -5
But a² and b² still have the exponentials.
i.e a² = (25 + 10√5)^⅔
b² = (25 - 10√5)^⅔
a² + b² will not simplify to (25² + (10√5)²) x 2,
You know how to become perfect square easyvproblrm please go and learn
A + B Perfect square is a square plus b square mijus two ab
A + B Perfect square is a square plus b square mijus two ab
We all know that.
The point is, you should be getting
50 = x((a+b)² - 2ab - ab)
50 = x(x² - 2(125)^⅓ - (125)^⅓)
50 = x (x² - 2(5) - 5)
50 = x(x² - 15)
50 = x³ - 15x
x³ - 15x - 50 = 0
Which is not what you wrote above
.
The point is, you should be getting
50 = x((a+b)² - 2ab - ab)
50 = x(x² - 2(125)^⅓ - (125)^⅓)
50 = x (x² - 2(5) - 5)
50 = x(x² - 15)
50 = x³ - 15x
x³ - 15x - 50 = 0
Which is not what you wrote above
.
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