Question

No 12 dan 13
pake caranya juga :)

Answer 1

12) Diketahui :
Keliling segitiga ABC = 12 cm
AB = x cm
BC = x+1 cm
AC = x+2 cm
Ditanya :
BC = ?
Jawab :
k = AB + BC + AC
12 = x + (x+1) + (x+2)
12 = 3x + 3
12-3 = 3x
9 = 3x
9/3 = x
3 = x
BC = x+1 = 3+1 = 4

13)Jawab :
 x+4 - 3x-4 < 1
-------  -------   ---
   4      2       2
x+4 - 2(3x-4) < 2
x+4 - 6x+8 < 2
x-6x < 2-4-8
-5x < -10
x > -10
     ------
       -5
x > 2