Move all terms to one side
4w^2 + 49 + 28w = 0
Rewrite 4w^2 + 49 + 28w in the form a^2 + 2ab + b^2, where a = 2w and b = 7
(2w)^2 + 2(2w)(7) + 7^2 = 0
Use the Square of Sum: (a + b)^2 = a^2 + 2ab + b^2
(2w + 7)^2 = 0
Take the square root of both sides
3w + 7 = 0
Subtract 7 from both sides
2w = -7
Divide both sides by 2
w = -7/2