Self
Maths Puzzle
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please slove it as early as possible
x^1/2 + y = 7
x + y^1/2 = 11
prove that x = 9 and y = 4
Read Solution (Total 2)
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- Let x^(1/2) = a and y^(1/2) = b
Therefore, a + b² = 7 ---------- (1)
a² + b = 11 ---------- (2)
Multiply (1) by a² and Multiply (2) by a,
a³ + a²b² = 7a² ---------- (1)
a³ + ab = 11a ---------- (2)
Subtract (1) and (2),
a²b² – ab = 7a² – 11a
-> ab(ab – 1) = a(7a – 11)
-> b(ab – 1) = (7a – 11)
-> ab² – b = 7a – 11
-> – b = 7a – ab² – 11
-> – b = a(7 – b²) – 11
a = (11 – b)/(7 – b²)
Let b = 1, 2,3,4 ...
when b = 2
a = (11 – b)/(7 – b²)
= (11 – 2)/(7 – 4) = 9/3 = 3
so a = 3 and b = 2 -> x^(1/2) = 3 and y^(1/2) = 2
Hence x = 9 and y = 4 - 10 years agoHelpfull: Yes(1) No(2)
- Sorry @tark,
but we cann't assume that a= --- and b= ---- now prove that - 10 years agoHelpfull: Yes(0) No(0)
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