(7-x)(7+x)+(x+3)^2

Expanding the first part:
(7-x)(7+x) = 49 - x^2

Expanding the second part:
(x+3)^2 = x^2 + 6x + 9

Putting it all together:
(7-x)(7+x) + (x+3)^2 = 49 - x^2 + x^2 + 6x + 9
= 49 + 6x + 9
= 58 + 6x

Therefore, (7-x)(7+x) + (x+3)^2 simplifies to 58 + 6x.