A. any list of ve real numbers is a vector in r5.
b. the vector u results when a vector u - v is added to the vector v.
e. the weights c1, . . ,cp in a linear combination cannot all be zero.
d. when u and y are nonzero vectors, span f {u, v} contains the line through u and the origin.
e. asking whether the linear system corresponding to an augmented matrix has a solution amounts to asking whether b is in span {a₁, a₂, a₃}.

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

a=24; b=12

step-by-step explanation:

a/b=2: 1

a=2b

36/(1+2)=12

b=12

a=24