The first three terms of a geometric sequence are as follows.
$- 5, 20, - 80$
Find the next two terms of this sequence. Give exact values (not decimal approximations).

Answer

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Answer

$a_{5} = a_{4} * r = 320 * - 4 = - 1280$

Steps

Step 1 ： $r = \frac{20}{- 5} = - 4$

Step 2 ： $a_{4} = a_{3} * r = - 80 * - 4 = 320$

Step 3 ： $a_{5} = a_{4} * r = 320 * - 4 = - 1280$