Question

49m^2+9n^2+16k^2-42mn-24nk-56mk​

Answer 1

(7m – 3n – 4k)2 =(7m)2 +(- 3n)2 +(- 4k)2 + [ 2

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

{ ∵(a + b +c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ac }

=49m2 + 9n2 + 16k2 + [ – 42mn ] + [ 24nk ] + [ – 56mk ]

= 49m2 + 9n2 + 16k2 – 42mn + 24nk – 56mk