find x if log2(x−5)>3
x>13
log2(x−5)>3
By definition of logarithm
x - 5 > 0
x > 5 ---------------(1)
Since base of logarithm greater than 1, then inequality is equivalent to
x - 5 > 23
x > 8 + 5
x > 13 -------------(2)
The common part of equation 1 and equation 2 is x > 13