Question 451767
Let's mark a number with x.
Product of that number and -15 is P1.


{{{P1 = -15x}}}


Product of that same number and 9 is P2.

{{{P2 = 9x}}}


It says that P1 decreased by 25 is by 23 greater than P2.


{{{P1-25 = P2+23}}}   , substitute P1 and P2 with above formulas
{{{-15x-25 = 9x+23}}} , move variables on the left and numbers on the right side
{{{-15x-9x = 23+25}}} , combine 
{{{-24x    = 48}}}    , divide both sides by -24
{{{   x    = -2}}}


Check:
P1 = -15*-2 =  30
P2 = 9*-2   = -18


P1-25 =  30-25 = 5
P2+23 = -18+23 = 5