<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: 
9514 1404 393
Answer:
0
Step-by-step explanation:
If a=b, you are asking for a whole number c such that ...
c = √(a² +a²) = a√2
If 'a' is a whole number, the only whole numbers that satisfy this equation are ...
c = 0 and a = 0.
0 = 0×√2
The lowest whole number c such that c = √(a²+b²) and a=b=whole number is zero.
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√2 is irrational, so there cannot be two non-zero whole numbers such that c/a=√2.
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<em>Additional comment</em>
If you allow 'a' to be irrational, then you can choose any value of 'c' that you like. Whole numbers begin at 0, so 0 is the lowest possible value of 'c'. If you don't like that one, you can choose c=1, which makes a=(√2)/2 ≈ 0.707, an irrational number. The problem statement here puts no restrictions on the values of 'a' and 'b'.
I think its 7,900 if not then you are correct
Answer: 2 soulutions
Step-by-step explanation: Just factor them and solve the answer would be x = 4 √3 + 8 in its exact form and x = 14.92820323... in its decimal form
Answer:
3,300
Step-by-step explanation: