Question 271214
Equation 1: {{{A = 4 + B}}}
Equation 2: {{{2A = 10 + 4B}}}

Solution:
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We can take the (4 + B) from equation 1 and substitute it into equation 2 for A
Equation 2: {{{2A = 10 + 4B}}}
{{{2*(4 + B) = 10 + 4B}}} Simplify
{{{8 + 2B = 10 + 4B}}} Subtract 10 from both sides
{{{8 + 2B - 10 = 4B}}} Subtract 2B from both sides
{{{8 - 10 = 4B - 2b}}} Simplify
{{{-2 = 2B}}} Divide both sides by 2
{{{highlight(-1 = B)}}}

Now we can plug -1 into equation 1 for B
Equation 1: {{{A = 4 + B}}}
{{{A = 4 + (-1)}}} Simplify
{{{highlight(A = 3)}}}

Check the answer:
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Plug your values back into equation 2
Equation 2: {{{2A = 10 + 4B}}}
{{{2*(3) = 10 + 4*(-1)}}} Simplify
{{{highlight(6 = 6)}}}