Question 1210391


let’s the numbers be {{{x}}} and {{{y}}}

if the sum of two numbers is {{{21}}}, we have

{{{x+y=21}}}.......solve for {{{x}}}

{{{x=21-y}}}...........eq.1

if five times the first number added to {{{2}}} times the second number is {{{66}}}. we have

{{{5x+2y=66}}}.......solve for {{{x}}}

{{{5x=66-2y}}}

{{{x=66/5-2y/5}}}............eq.2


from eq.1 and eq.2 we have

{{{21-y=66/5-2y/5}}}.........both sides multiply by {{{5}}}

{{{105-5y=66-2y}}}

{{{105-66=5y-2y}}}

{{{39=3y}}}

{{{39/3=y}}}

{{{y=13}}}

go to

{{{x=21-y}}}...........eq.1, substitute {{{y}}}

{{{x=21-13}}}

{{{x=8}}}

so. your numbers are {{{8}}} and {{{13}}}