Question 965511
what is the first number of a geometric sequence if the next two numbers are 3 and 17
<pre>

Let the first term be x:

The sequence goes

x, 3, 17

2nd term ÷ 1st term = 3rd term ÷ 2nd term
    3    ÷     x    =    17    ÷    3
          
Get the equation all together:

                3÷x = 17÷3
                {{{3/x = 17/3}}}

Cross multiply:

                  9 = 17x

Divide through by 17

               {{{9/17}}} = x
                  

The sequence is {{{9/17}}}, 3, 17  

Answer: {{{9/17}}}
             
Edwin</pre>