Question 762324
Equation 1: {{{A + B = 63}}}
Equation 2: {{{5A = 4B}}}
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Solve one of the equations for one of the variables.
I will solve equation 2 for A by dividing both sides by 5.
Equation 2: {{{5A = 4B}}}
{{{A = (4/5)B}}}
Now plug (4/5)B into equation 1 for A.
Equation 1: {{{A + B = 63}}}
{{{(4/5)B + B = 63}}}
B by itself can also be written as 1B or (5/5)B. They are all equal.
{{{(4/5)B + (5/5)B = 63}}}
Combine like terms.
{{{(9/5)B = 63}}}
Multiply both sides by 5/9
{{{cross((5/9)*(9/5))*B = 63*(5/9)}}}
{{{highlight(B = 35)}}}
Now solve for A.
{{{A = (4/5)B}}}
{{{A = (4/5)*35}}}
{{{highlight_green(A = 28)}}}