Question 902239
Let D = Number of Dogs
Let C = Number of Cats
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Equation 1: {{{D = 3C}}}
Equation 2: {{{D + C = 28}}}
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Plug 3C into equation 2 for D
Equation 2: {{{D + C = 28}}}
{{{(3C) + C = 28}}}
Combine like terms.
{{{4C = 28}}}
Divide both sides by 4
{{{highlight(C = 7)}}}
Now plug 7 into equation 1 for C
Equation 1: {{{D = 3C}}}
{{{D = 3*(7)}}}
{{{highlight_green(D = 21)}}}