Use the definition of logarithm to simply each expression
log lower 10 ^10-4
by definition, log_10(10^n) = n
so, log_10(10^-4) = -4
Or, you can recall that log x^n = n*logx
Since log_10(10) = 1, we again have -4*1 = -4
log lower 10 ^10-4
so, log_10(10^-4) = -4
Or, you can recall that log x^n = n*logx
Since log_10(10) = 1, we again have -4*1 = -4