



 
Hi Hannah, I am going to change your madeup number to $ \$523$, then if $x$ is the number of kids and y is the number of adults the equations become \[5x + 8y = 523\] \[x + y = 71\] At this point multiply both sides of the second equation by $5$ so the equations become \[5x + 8y = 523\] \[5x + 5y = 355\] These equations can then be rewritten \[5x = 523  8y\] \[5x = 355  5y\] Since both right sides are equal to $5x$ they must be equal and hence \[ 523  8y = 355  5y\] Solve for $y.$ This is probably not the way your textbook or teacher would present the solution. I expect they would multiply both sides of the second equation by $5$ as I did to get \[5x + 8y = 523\] \[5x + 5y = 355\] but the next step would be to "subtract the second equation from the first equation".
and hence subtracting the second equation from the first yields \[3y = 168\] Solve for y. I hope this helps,  


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