F4 Equation of Staright Lines

Let m > 0 be the slope ,

then the equation of a straight line passing through (-4,7) is

(y - 7) / (x - (-4)) = m

y - 7 = m(x + 4)

mx - y + 4m+7 = 0

Put m = 1 ,

x - y + 11 = 0 is one of the equation of a straight line passing through (-4,7).

2012-02-04 14:17:19 補充：
好啦,一題咁多啦~

求其在 quadrant IV 找兩點 : (1 , - 1) , (1 , - 2)

用兩點式 :

(y - 0) / (x - 0) = (- 1 - 0) / (1 - 0)
y / x = - 1
x + y = 0

及

y / x = - 2 / 1
2x + y = 0

我都知
不過幫忙拉
+_+ Thank you

2012-02-04 13:57:26 補充：
你可以幫我答多一題嗎?

If a straight line passes through the origin and quadrant IV, suggest two possible equation of the straight line.

*please answer in complete step*
*-* Thank you

得一點..好難計嫁喎...