3. If x + 4, 2x+5, and 4x + 3 represent the first three terms of an arithmetic sequence, then find the

value of x. What is the fourth term?

first term = initial number

second term = initial number + common difference

third term = initial number + 2 (common difference)

So ...

2x+5 - (x+4) = common difference

4x+3 - (2x+5) = also common difference

2x+5 - (x+4) = x+1

4x+3 - (2x+5) = 2x-2

Because x+1=2x-2 we can solve for x.

x=3

So the sequence goes ... 7,11,15 ...

19 is the fourth term