Not necessarily.

and

may be linearly dependent, so that their span forms a subspace of

that does not contain every vector in

.
For example, we could have

and

. Any vector

of the form

, where

, is impossible to obtain as a linear combination of these

and

, since

unless

and

.
Answer:
x = 3
Step-by-step explanation:
the line doesn't have a slope
Substitute y=4x to the second equation:
x^2 + (4x)^2 = 17
x^2 + 16x^2 = 17
17x^2 = 17
x^2 = 17/17
x^2 = 1
x = 1 and -1
When x=1, y=4(1) = 4
When x=-1, y=4(-1) = -4
Thus the solutions would be (1,4) and (-1,-4). That would correspond to D. and A.
One way to do this is use the fact that the exterior angles of all polygons add up to 360 degrees
So an exterior angle of a regular octagon = 360 / 8 = 45 degrees.
So each interior angle = 180 - 45 = 135 degrees
so total measure of all angles in octagon = 8 * 135 = 1080 degrees
Easy
if x is the number
sqrt x is between 17 and 18
17<√x<18
squaer the whole thing
289<x<324
x could be 300
it could be sqrt of 300
√300=10√3
one is 10√3