Question

Evaluate 9yl – yº if y = – 8.-71-73- 2- 64

Answer 1

First of all, we need to rules to solve this:

$\begin{gathered} a^0=1,a\ne0 \\ a^1=a,a\text{ any number} \end{gathered}$

So, the equation to be evaluated can be reduced to:

$\begin{gathered} y=-8\Rightarrow9y^1-y^0=9y-1 \\ \Rightarrow9y^1-y^0=9\cdot(-8)-1=-72-1=-73 \\ \Rightarrow9y^1-y^0=-73 \end{gathered}$

Then, the answer is -73, the second option