AMC 10B 2002 Problem 20

Past Contests AMC 10 AMC 10B - 2002
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1

Let a, b, and c be real numbers such that a-7 b+8 c=4 and 8 a+4 b-c=7. Then a^{2}-b^{2}+c^{2} is

Answer Choices
A. 0
B. 1
C. 4
D. 7
E. 8