Question

The value of $x$ so that $(-5{)}^{x+1}\times (-5{)}^5=(-5{)}^7$ is

• A. -1
• B. 2
• C. 1

Answer 1

The correct option is C 1

$(-5{)}^{x+1}\times (-5{)}^5=(-5{)}^7$
$\Rightarrow (-5{)}^{x+1+5}=(-5{)}^7$
$\Rightarrow (-5{)}^{x+6}=(-5{)}^7$

$\therefore x+6=7$
$\Rightarrow x=7-6=1$