# What is the missing term in this geometric sequence ..., -32, __, -128, ...?

Dec 6, 2016

color(purple)(-64 or color(violet)(64

#### Explanation:

A geometric sequence is a series in which the number succeeding the first number is got by multiplying the previous number with some fixed ratio, this ratio is known as the common ratio

color(purple)(-32^(xx2),-64^(xx2),-128^(xx2)....

The common ratio in this sequence is $2$

So,

-32*2=color(purple)(-64

And

$\textcolor{p u r p \le}{- 64} \cdot 2 = - 128$

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But, the common ratio can also be $- 2$ ans the missing number can be $64$

color(violet)(-32^(xx-22),64^(xx-12),-128^(xx-2)....

So,

-32*-2=color(violet)(64

And

$\textcolor{v i o \le t}{64} \cdot - 2 = - 128$