Odpowiedź :
[tex]12ac + 13 {c}^{2} + 14 {a}^{2} - 8 {a}^{2} - 7 {a}^{2} - 8ac = 4ac + 13 {c}^{2} - {a}^{2} [/tex]
[tex]12ac + 13c^2 + 14a^2 - 8a^2 - 7a^2 - 8ac\\\\4ac + 13c^2 - a^2[/tex]
[tex]12ac + 13 {c}^{2} + 14 {a}^{2} - 8 {a}^{2} - 7 {a}^{2} - 8ac = 4ac + 13 {c}^{2} - {a}^{2} [/tex]
[tex]12ac + 13c^2 + 14a^2 - 8a^2 - 7a^2 - 8ac\\\\4ac + 13c^2 - a^2[/tex]