1.Raka mempunyai kelereng tiga kali lebih banyak dari Adi,total kelereng yang mereka punya adalah 19 kelereng. 》Berapa kah kelereng yang adi punyai? 》berapakah

[tex]raka = x \\ adi = y \\ x = 3y \\ x + y = 19 \\ subs \: x = 3y \\ x + y = 19 \\ 3y + y = 19 \\ 4y = 19 \\ y = \frac{19}{4} \\ subs \: y = \frac{19}{4} \\ x = 3y \\ x = 3 \times \frac{19}{4} \\ x = \frac{57}{4} \\ raka = \frac{57}{4} \\ adi = \frac{19}{4} \\ \\ \frac{1}{2} (x - 4) < 4 + \frac{4}{5} x \\ \frac{(x - 4)}{2} < 4 + \frac{4}{5} x \\ x - 4 < 2(4 + \frac{4}{5} x) \\ x - 4 < 8 + \frac{8}{5} x \\ x - \frac{8}{5} x < 8 + 12 \\ - \frac{3}{5} x < 20 \\ x > 20 \times - \frac{5}{3} \\ x > - \frac{100}{3} [/tex]
[tex] \frac{2y - 5}{4} + \frac{7}{12} = 4y - \frac{1}{3} \\ \frac{2y - 5}{4} - 4y = - \frac{1}{ 3} - \frac{7}{12} \\ \frac{2y - 5 - 16y}{4} = \frac{ - 4 - 7}{12} \\ 12( - 14y - 5) = 4( - 11) \\ - 168y - 60 = - 44 \\ - 168y = - 44 + 60 \\ - 168y = 16 \\ y = - \frac{16}{168} [/tex]
[tex] \frac{2x + 3}{5} = \frac{x + 1}{3} \\ 3(2x + 3) = 5(x + 1) \\ 6x + 9 = 5x + 5 \\ 6x - 5x = 5 - 9 \\ x = - 4[/tex]