Let's consider an arbitrary 2x2 matrix as an example,

The columns of

are linearly independent if and only if the column vectors

are linearly independent.
This is the case if the only way we can make a linear combination of

reduce to the zero vector is to multiply the vectors by 0; that is,

only by letting

.
A more concrete example: suppose

Here,

and

. Notice that we can get the zero vector by taking

and

:

so the columns of

are not linearly independent, or linearly dependent.
Answer:
See explanation.
Step-by-step explanation:
2) Your written answer is correct, y = x +4
3) Slope of perpendicular line: 5/2
y=mx+b
4 = (5/2)(4) + b
4 = 10 + b
b = -6
So, y=(5/2)x - 6
4) Slope of perpendicular line: 1
y=mx+b
5 = (1)(4) + b
5 = 4 + b
b = 1
So, y = x + 1
7) Slope of perpendicular line: 3/4
y=mx+b
4 = (3/4)(4) + b
4 = 3 + b
b = 1
So, y = (3/4)x + 1
8) Slope of perpendicular line: 1/4
y=mx+b
-2 = (1/4)(0) + b
b = -2
So, y = (1/4)x - 2
The fraction is 4 1/2. Just convert the decimal into a fraction. 50/100 is the same as 5/10 which is the same as 1/2.
Given that the number of years should be represented with x, the number of fish in the pond after x years should best be represented with f(x). The equation that would best show the given scenario in the problem above is,
f(x) = 500(2^x)
From the given, 500 is used as the initial population of the fish.