Replace your expression for h2 in c2=h2+b2-2bx+x2.
Answer
A
C2 = a2 - x2 + b2 - 2bx + x2
B
c2 = a2 + x2 + b2 - 2bx + x2
C
c2 = -a2 - x2 + b2 - 2bx + x2
Explanation
Using the earlier expression h² = a² − x², substitute it for h² in c² = h² + b² − 2bx + x². This gives c² = a² − x² + b² − 2bx + x², which matches choice A.
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