Question 291657
First name your variable "a number".
How about N?
3 times a number,
{{{3N}}}
Decreased by 5 (subtract 5 from it), so all put together. 
{{{3N-5}}}
Doubled,
{{{2(3N-5)}}}
The result means "="
Twice the number,
{{{2N}}}
14 less than twice the number
{{{2N-14}}}
So now put the left hand side and the right hand side together along with "="
{{{2(3N-5)=2N-14}}}