Answer:
336
Step-by-step explanation:
Given the expansion: [tex](7+4x)^3[/tex]
[tex](7+4x)^3\\\\=(7+4x)^2*(7+4x)\\\\=(7+4x)(16x^2+56x+49)\\\\=7(16x^2+56x+49)+4x(16x^2+56x+49)\\\\=112x^2+392x+343+64x^3+224x^2+196x\\\\=64x^3+112x^2+224x^2+392x+196x+343\\\\=64x^3+336x^2+588x+343[/tex]
Therefore, the coefficient of the second term is 336.
