# If the $4^{th}$ term of a GP is the square of its second term and the first term is -2. Find the $7^{th}$ term of the GP.

$\begin{array}{1 1} 64 \\ 128 \\ -64 \\ -128 \end{array}$

Explanation :
$Given\;T_{4}=T_{2}^2$
$ar^3=a^2r^2$
$a=-2$
$r=a$
$r=-2$
$T_{7}=ar^6=(-2)(-2)^6$
$=-128.$