6.diketahui fungsi f (x) =a x + b jika f(-5) = 15 dan f(3) = -1 maka hasil dari 2a + 3 b adalah... 7.persamaan garis yang melalui A (5,-2) dan B (-3,4

6. f(x) = ax + b
   f(-5) = -5a + b
  15 = -5a + b
   f(3) = 3a + b
   -1 = 3a + b
  15 = -5a +b
  -16 = 8a
a = -2
-5a + b = 15
-5(-2) + b = 15
10 + b = 15
b = 5
f(x) = -2x + 5
maka 2a + 3b = 2(-2) + 3(5) = -4 + 15 = 11

7. (y-y1)/(y2-y1) = (x-x1)/(x2-x1)
(y  - 4) / (-2 - 4) = (x - 5) / (-3 - 5)
(y-4) / -6 = (x-5) / -8
-8 (y - 4) = -6 (x - 5)
-8y + 32 = -6x + 30
-8 y = -6x -2
 8y = 6x + 2
 8y - 6x -2 = 0