黄斌
幼苗
共回答了14个问题采纳率:92.9% 举报
x = 1,则 y = 1 ;
x = -1 ,则 y = 5 ;
x = -3 ,则 y = 17 ;
列方程组,就是
a + b + c = 1
a - b + c = 5
9a - 3b + c = 17
a - b + c - a - b - c = 5 - 1
-2b = 4
b = -2
a - 2 + c = 1
a + 2 + c = 5
a + c = 3
9a - 3b + c - a - b - c = 17 - 1
8a - 4b = 16
2a - b = 4
2a + 2 = 4
a + 1 = 2
a = 1
a + c = 3
1 + c = 3
c = 2
y = x" - 2x + 2
1年前
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