help.. maths exam revision?

Question

THe value of x in log(subscript 3) 3^(x-2) - log (subscript 2) 32 + log (subscript x) x^2 = 5 is:

A. -4
B. 0
C. 6
D. 8
E. None of these

Answer 1

E. None of these.

That's because x = 10. How so? :

log_3 [3^(x - 2)] = (x - 2); log_2 [32] = 5; and log_x [x^2] = 2.

So we have (x - 2) - 5 + 2 = 5, that is x = 10.

This is neither answer A nor B nor C nor D; hence the answer is:

E. None of these.

Live long and prosper.

Answer 2

simply substitute the choices given and use this form in log problem for easier solution:

((log 3^(x-2))/log3) - (log32)/(log 2) + (log x^2)/(log x)

then subtitute:

when x= -4; math error
x= 0; math error
x= 6; 1
x= 8; 3
so none of the above

Answer 3

x-2 - 5 + 2 = 5
x = 10, E none of these

Answer 4

log[3] 3^(x-2) = x-2
log[2] 32 = 5
log[x] x² = 2
the log is the exponent, so you have
x-2 - 5 + 2 = 5
x = 10
E.