Jawabanmu

2014-04-19T20:25:46+07:00
Bx - ay = bx1 - ay1 4x - (-2)y = 4(10) - (-2)-8 4x + 2y = 40 -16 4x + 2y = 24 4x + 2y - 24 = 0
2014-04-19T20:33:07+07:00
1.) rasio (r) = 3 : 1 = 3

S₆ = a .  \frac{r^{n}-1 }{r-1}

     = 1 .  \frac{ 3^{6}-1 }{3-1}

     = 1 .  \frac{728}{2}

     = 1 . 364
     = 364

2.) m₁ =  \frac{-a}{b}

          =  \frac{-(-2)}{4} =  \frac{1}{2}

karena tegak lurus garis maka gradiennya adalah
m₁ . m₂ = -1

 \frac{1}{2} . m₂ = -1

m₂ =  \frac{-1}{ \frac{1}{2} }

m₂ = -2

rumus persamaan garisnya adalah
y-y₁=m(x-x₁)

y-(-8) = -2(x-10)
y = -2x + 20 -8
y = -2x + 12

semoga sukses :)