sunlight's answer to sunlight's Secondary 3 A Maths Singapore question.
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Where did I did wrongly,am not suppose to make it to 2 equations?
Date Posted:
3 years ago
Again, you didn't simplify the equations.
8c√3 + c² = 8√3 + 49 - 48
8c√3 + c² = 8√3 + 1
Comparing coefficients of √3,
8c = 8
c = 1
Comparing coefficients of c²,
c² = 1
c = 1 or = -1(rejected as that would make 8c = -8, which is negative andwould not equal the 8 on the RHS)
8c√3 + c² = 8√3 + 1
Comparing coefficients of √3,
8c = 8
c = 1
Comparing coefficients of c²,
c² = 1
c = 1 or = -1(rejected as that would make 8c = -8, which is negative andwould not equal the 8 on the RHS)
Alternatively,
8c√3 + c² = 8√3 + 1
c² + 8√3 c - (8√3 + 1) = 0
(c - 1)(c + 8√3 + 1) = 0
c - 1 = 0 or c + 8√3 + 1 = 0
c = 1 or c = -8√3 - 1 (rejected , as this would mean the side of the square = 4√3 - 8√3 - 1
= -4√3 - 1, which is negative and we know that length cannot be negative)
So, c = 1
8c√3 + c² = 8√3 + 1
c² + 8√3 c - (8√3 + 1) = 0
(c - 1)(c + 8√3 + 1) = 0
c - 1 = 0 or c + 8√3 + 1 = 0
c = 1 or c = -8√3 - 1 (rejected , as this would mean the side of the square = 4√3 - 8√3 - 1
= -4√3 - 1, which is negative and we know that length cannot be negative)
So, c = 1
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