Answers:
The system of equations is
[tex]\begin{cases}y = x-5\\x+y = 19\end{cases}[/tex]
where x and y is the number of right-handed and left-handed people respectively.
The system solves to (x,y) = (12,7)
Interpretation:
There are 12 right-handed people and 7 left-handed people in the class.
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Explanation:
x = number of right-handed people
y = number of left-handed people
x and y are positive whole numbers.
There are 5 more right-handed people compared to left-handed people, so we can say x = y+5 which is the same as y = x-5. So you could go for either equation. Let's go for the one where y is isolated.
The second equation to form is x+y = 19 because there are 19 people in the class, and you can only be one or the other (left-handed or right-handed but not both). I'm not considering the possibility anyone is ambidextrous though of course that may happen in a realistic setting.
The two equations then form the system
[tex]\begin{cases}y = x-5\\x+y = 19\end{cases}[/tex]
There are a number of ways we can solve this system. Substitution is possibly the quickest way.
x+y = 19
x+(x-5) = 19 ... replace y with x-5; due to the first equation
2x-5 = 19
2x = 19+5
2x = 24
x = 24/2
x = 12 .... this is the number of right-handed people
y = x-5
y = 12-5
y = 7 .... this is the number of left-handed people
