Question

(a+4)²-5ab-20b-6b² factorise

Answer 1

$(a + 4 ) { }^{2} = a {}^{2} + 4 {}^{2} + 2 \times a \times 4$
$(a + 4) {}^{2} = a {}^{2} + 16 + 8a$
$(a + 4) {}^{2} - 5ab - 20b - 6b {}^{2} = a {}^{2} + 16 + 8a - 5ab - 20b - 6b {}^{2}$