Problem Solving

Hello,

As I was going through my test these two questions came up. As I cannot explain them, you guessed that I got them both wrong... looks like I like losing easy points...doesn't it...

HELP....

1:

Cubic Root of x-b= c^6 then X=

1/ c^2 +b
2/ c^6 +b
3/ c^9 +b
4/ c^12+b
5/ c^18+b

2:

3^x - 3^x-1 = 162 Then x(x-1) =

1/ 12
2/ 16
3/ 20
4/ 30
5/ 81

Thank you for any help anyone can give me!!!!

I will post the official answers later if necessary,

JB

1) Get rid of the cube root term on LHS

(X-B) ^ 1/3 = C^6

Cube both sides

x-b = c^18
x = c^18+b

E)

2) 3^x - 3^x-1 = 162 Then x(x-1) =

LHS: 3^X - 3^X 3^-1 = 162 (a^b+c = a^b * a ^ c where a=3 b=x c=-1 also 3^-1= 1/3^1 since a^ - exp = 1/a^exp))

TAKING 3^X THE COMMON FACTOR OUT

3^X(1 - 1/3) = 162
3^X 2/3 = 162
3^X = 162*3/2
3^X = 81*3
3^X = 3^5

X=5 THEREFORE X-1=4

5*4 = 20

C)

Clear and easy...

Thank you for your help!

LHS stand for what exactly (English not my native language obviously...)

JB

jbramet wrote:Clear and easy...

Thank you for your help!

LHS stand for what exactly (English not my native language obviously...)

LHS: Left hand side
RHS: Right hand side

a + b = c+d
LHS= a+b
RHS= c+d

JB