(2a+b+3c)pangkat 2. Jwb dong buat besokk

[tex](2a + b + 3c) {}^{2} \\ = (2a + b + 3c)(2a + b + 3c) \\ = 4 {a}^{2} + 2ab + 6ac + 2ab + {b}^{2} + 3bc + 6ac + 3bc + 9 {c}^{2} \\ = 4 {a}^{2} + {b}^{2} + 9 {c}^{2} + 2ab + 2ab + 6ac + 6ac + 3bc + 3bc \\ = 4 {a}^{2} + {b}^{2} + 9 {c}^{2} + 4ab + 12ac + 6bc[/tex]
sambil dikoreksi ya :)