Answer:
[tex]x^{4}+28x^3+294x^2+1372x+2401[/tex]
Step-by-step explanation:
[tex](x+7)^{2} (x+7)^2 = (x+ 7)(x+7)(x+7)(x+7)\\(x^2+7x+7x+49)(x^2+7x+7x+49)=(x^2+14x+49)(x^2+14x+49)\\x^4+14x^3+49x^2+14x^3+196x^2+686x+49x^2+686x+2401\\x^4+28x^3+294x^2+1372x+2401[/tex]
