Question

determine o valor da expressão :
log28+ log5 25+log7 49+ log7 1

Answer 1

$log\ _2\ 8 = x\\\\ 2^x = 8\\\\ 2^x=2^3\\\\ \boxed{x=3}\\\\\ log\ _5\ 25 = x\\\\ 5^x = 25\\\\ 5^x = 5^2\\\\ \boxed{x=2}$

$log\ _7\ 49 = x\\\\ 7^x = 49\\\\ 7^x = 7^2\\\\ \boxed{x=2}\\\\\ log\ _7\ 1 = x\\\\ 7^x = 1\\\\ 7^x = 7^0\\\\ \boxed{x=0}$

$3+2+2+0 = \boxed{7}$