<em>Correct expression: </em>
Answer:
x = 4
x = -4
x = 7i or 
x = -7i or 
Step-by-step explanation:

We do factorization of x^2 - 16
(x^2-16) = (x+4)(x-4)
(x+4)(x-4)(x^2+49) = 0
We require that any term in the multiplication to be zero to fulfil the requirement
so:
if x + 4 = 0 then (x+4)(x-4)(x^2+49) = 0
x = -4
if x - 4 = 0 then (x+4)(x-4)(x^2+49) = 0
x = 4
if (x^2+49) = 0 then (x+4)(x-4)(x^2+49) = 0
x^2 = -49
we have two roots:
If your course has already worked with complex number and the root of -1 then:
7i and -7i are solution as well
because 7i will be: 
and the same reasoning for -7i: 
Answer:
Did you attached an image? I can't see it
Step-by-step explanation:
Answer:
<h2>x = 4</h2>
Step-by-step explanation:
Look at the picture.
We have the triangles 30° - 60° - 90° and 45° - 45° - 90°.
The sides are in proportions:
30° - 60° - 90° ⇒ 1 : √3 : 2
45° - 45° - 90° ⇒ 1 : 1 : √2
======================================================

Answer:
c. x>4
Step-by-step explanation:
subtract 7 from both sides. 11-7=4
x>4