Question 1078440
let's numbers be {{{x}}} and {{{y}}} where {{{y}}} is the smaller number

if the sum of two numbers is {{{18}}}, we know that

{{{x+y=18}}}........solve for {{{x}}}

{{{x=18-y}}}.........eq.1

if twice the smaller number {{{decreased}}} by three equals the larger number, we have
{{{x=2y-3}}}.....eq.2

in eq.1 and eq.2 we see that left sides are equal; so, right sides are equal too

{{{18-y=2y-3}}}....solve for {{{y}}}

{{{18+3=2y+y}}}

{{{21=3y}}}

{{{y=21/3}}}

{{{y=7}}}

go to {{{x=2y-3}}}.....eq.2, substitute {{{y}}} and solve for {{{x}}}

{{{x=2*7-3}}}

{{{x=14-3}}}

{{{x=11}}}


so, your two numbers are {{{11}}} and {{{7}}}