Question 271406
Equation 1: {{{A + B = 24}}}
Equation 2: {{{5A - B = 12}}}

Solve equation 1 for one of the variables.
Equation 1: {{{A + B = 24}}}
{{{A = 24 - B}}}

Now plug (24 - B) into equation 2 for A
Equation 2: {{{5A - B = 12}}}
{{{5*(24-B) - B = 12}}} Simplify
{{{120 - 5B - B = 12}}} Combine like terms
{{{120 - 6B = 12}}} subtract 120 from both sides
{{{-6B = -108}}} divide both sides by -6
{{{highlight(B = 18)}}}

Now plug 18 into equation 1 for B
Equation 1: {{{A + B = 24}}}
{{{A + 18 = 24}}}
{{{highlight(A = 6)}}}