Given that the roots of the equation x^2-6x+c=0 are 3+8i and 3-8i, the value of c can be obtained as follows;
taking x=3+8i and substituting it in our equation we get:
(3+8i)^2-6(3+8i)+c=0
-55+48i-18-48i+c=0
collecting the like terms we get:
-55-18+48i-48i+c=0
-73+c=0
c=73
the answer is c=73
Answer:

Step-by-step explanation:
Let:

We need to eliminate one of the variables, so let's use elimination method. First multiply (1) by 2

Now subtract (2) from 2*(1) in order to eliminate x:

Solving for y:
Multiplying both sides by -1

Finally, replacing the value of y in (1)

Solving for x:
add 41 to both sides:

Multiply both sides by 1/2:

Slot method or permutations
top 3
6 for first slot
5 for 2nd slot
4 for 3rd
6*5*4=120
120 possiblites
answer is C
Let's say the number is x
75%of x is 15
75%x=15
0.75x=15
x=15/0.75
x=20
or you can say 3/4x=15
x=15*4/3
x=20