Question 49285
<pre><font size = 5><b>Can you please solve.

<u>x  1  2  3  4</u> 
a 18 16 14 12

a=????
Thanks Brad

something like x + 8 -6!!!!!!!!!!

-------------------------------


The successive values of "a" differ by -2
But the successive values of "x" differ by only 1
However the successive values of "2x" will differ by 2

So let's put in a list between them for 2x

<u> x  1  2  3  4</u>  
<u>2x  2  4  6  8</u>
<u> a 18 16 14 12</u>

Now we can observe that 2+18=20, 4+16=20, 6+14=20, 8+12=20

So it must be that 2x + a must equal 20, or

2x + a = 20, or solving for a

     a = 20 - 2x.

So the answer is 20 - 2x

Edwin</pre>