Is it so difficult for you to write the post accurately ?

Let us present the unknown number N in decimal form via its "tens" digit "t"  and  "ones" digit "u"  N = 10*t + u.


Then the condition says

t = u + 5                   (1)
10*t + u = 3*t*u - 14.      (2)


It is your system of equations to solve.

From (1), substitute the expression for "t" into equation (2). You will get

10*(u+5) + u = 3*(u+5)*u - 14,

10u + 50 + u = 3u^2 + 15u - 14,

3u^2 + 4u - 64 = 0,

 =  = .


The only integer positive solution is u = 4.

Then   t = u+5 = 9.


The number is  94.