Variable: x; which represents Elijah's height since we don't know how tall he is.
Equation: x+6=42
"Samuel is six inches taller than" → +6
"His brother Elijah" → x
"Samuel is 48 inches tall" → =48
Solution: 42 inches
You can solve the equation by subtracting 6 from both sides to isolate x.
x+6-6=48-6
x=42
Therefore, Elijah is 48 inches tall.
If you substitute x into the original equation, the answer is still true.
42+6=48
48=48
