There is a triangle with sides , and , where , and satisfy the equations and . Find the perimeter of .
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Using Completing the Square to the equation b c = a 2 − 1 2 a + 5 2 , turn the equation into
b c = ( a − 6 ) 2 + 1 6
From the equation, we can know that b c ⩾ 1 6 .
Similarly, from the equation b + c = 8 , we can know that b c ⩽ 1 6 .
From the two equations
b c ⩾ 1 6
b c ⩽ 1 6
We can know that b c = 1 6
b c = ( a − 6 ) 2 + 1 6
( a − 6 ) 2 = 0
a = 6
∴ a + b + c = 1 4