八年级数学题,求过程,凡是解答就完美答案,急急急
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共1个回答
热心网友
(1)
x=3, y=0, 3k+b=0, b = -3k, y = k(x-3$
C(0, -3k)
B: y=4=-4m/3, m = -3, B(-3, 4)
4=k(-3-3), k= -2/3, b = -3k = 2
y = -2x/3 + 2
(2)
AB的中点为M(0,2), 其中垂线的斜率为-1/(-2/3) = 3/2
中垂线的方程y = 3x/2 + 2
令D(a, 3a/2)
AB² = (-3-3)² + (4 -0 )² = 52 = 2AD² = 2[(a - 3)² + (3a/2 + 2 - 0)²]
a² = 4
a = 2, D(2, 5)
舍去a = -2 < 0
热心网友
(1)
x=3, y=0, 3k+b=0, b = -3k, y = k(x-3$
C(0, -3k)
B: y=4=-4m/3, m = -3, B(-3, 4)
4=k(-3-3), k= -2/3, b = -3k = 2
y = -2x/3 + 2
(2)
AB的中点为M(0,2), 其中垂线的斜率为-1/(-2/3) = 3/2
中垂线的方程y = 3x/2 + 2
令D(a, 3a/2)
AB² = (-3-3)² + (4 -0 )² = 52 = 2AD² = 2[(a - 3)² + (3a/2 + 2 - 0)²]
a² = 4
a = 2, D(2, 5)
舍去a = -2 < 0
