中四數學問題 急急急10點

1 Let x = 0, y = 2. A(0,2)

Using two - point form, the equation of the straight line passing through A and B(2,-1) is

(y - 2)/x = (-1 - 2)/(2 - 0)

2y - 4 = -3x

3x + 2y - 4 = 0

2 The slope of the line perpendicular to L is 5/4

The equation of the straight the passing through P(2,-1) and perpendicular to L

y + 1 = (5/4)(x - 2)

5x - 4y - 14 = 0

1)sub x=0 into x+3y-6=0
0+3y-6=0
3y-6=0
y=2
therefore A=(0,2)
slope of AB=(2-(-1))/(0-2)
=-3/2
because A=(0,2)
therefore y-intercept of AB=2
y=(-3/2)x+2
2y=-3x+4
3x+2y-4=0
2)slope of L=-4/5
because the straight line is prependicular to L.
therefore slope of the straight line=5/4
y-(-1)=(5/4)(x-2)
y+1=(5/4)(x-2)
4y+4=5x-10
5x-4y-14=0

1) x+3y-6=0

slope: -1 over 3

Eqn:
y-(-1)=-1 over3(x-2)
3y+3=-x+2
x-3y-1=0

2) 我想問下你有冇line L既slope?(因為題目有題到)
因為 L: 4x+5y-10=0同line L係perpendicular,
如果有就可以唔洗自己另外再計個slope,
淨係將要知兩條line個slope相乘=-1
如果冇我就計理俾你

L: 4x+5y-10=0

slope: -4 over 5

Eqn:
(y+1)=-4 over5 (x-2)
5y+5=-4x+8
4x+5y-3=0

－－－－－
個slope既計法:
當Ax+By+C=0
Slope=-A over B