Question 943759

Jack is twice as old as Jill. 
{{{Jack=2*Jill}}}....eq.1


In two years Jack will be four times as old as Jill was nine years ago. 

{{{Jack+2=4*(Jill-9)}}}....eq.2

How old are they now?; solve the system:

{{{Jack=2*Jill}}}....eq.1
{{{Jack+2=4*(Jill-9)}}}....eq.2....substitute Jack from eq.1


{{{2*Jill+2=4*(Jill-9)}}}....eq.2

{{{2*Jill+2=4*Jill-36}}}

{{{36+2=4*Jill-2*Jill}}}

{{{38=2*Jill}}}

{{{38/2=Jill}}}

{{{highlight(Jill=19)}}}

then

{{{Jack=2*Jill}}}....eq.1

{{{highlight(Jack=38)}}}