Question

25 a^2 -4a^2+18bc-47c^2

Answer 1

sorry I can't understand the question

Answer 2

$25 {a}^{2} - 9{b}^{2} + 12bc - 4 {c}^{2} \\ = 25 {a}^{2} - {(3b - 2c) }^{2} \\ (5a + 3b - 2c)(5a - 3b + 2c)$