Question 1101301
k Kathy
b Bill
x Sally


{{{system(k=b+7,x=k-5,k+b+x=45)}}}


Make these substitutions in the age-sum equation:  {{{system(b=k-7,x=k-5)}}}


{{{k+(k-7)+(k-5)=45}}}------one equation in one unknown variable.

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{{{3k-12=45}}}
{{{3k=57}}}
{{{highlight(k=19)}}}-----Kathy

{{{highlight(Bill=12)}}}

{{{highlight(Sally=14)}}}


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check:
19+12+14=30+9+6+6=30+15=45
ok