✔ 最佳答案
Let the coordinate of point A is (x,0)
(a). 6x/2=12
x=4
(b). Gradient of the line is 6/4=3/2
So, the line is y-6=(3/2)(x-0)
y=(3/2)x+6
Compare y=(3/2)x+6 with y=ax+b,
a=3/2, b=6
(c). Substitute -2=x, 4=y
RHS=(3/2)*(-2)+6
=3
≠LHS
So, (-2,4) is NOT on the line.
2011-08-30 12:41:06 補充:
CORRECTION!!
(a). 6x/2=12
x=4
In the graph, we can see that x is negative,
so x=-4
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