Question

expand it (7m - 3n – 4k)²
I won't in full method and formula please help me ​

Answer 1

Answer:

(7m)^2 + ( -3n)^2 + ( -4k)^2 +[ 2×(7m)×(-3n)] + [ 2× (-3n)×(-4k)] + [ 2×( -4k) ×(7m)]

49m^2 +9n^2 + 16k^2 - 42mn + 24nk - 56km

(a^2 +b^2 +c^2) = a^2+ b^2 +c^2+ 2ab +2bc +2ca