To solve the word problem, we need to determine how many miles Cameron had already traveled when he passed the sign. Let's break down the problem step-by-step.
1. Let [tex]\( x \)[/tex] represent the distance Cameron has already traveled.
2. According to the problem, the total distance from Cameron's house to the beach is 46 miles.
3. When Cameron passed the sign, there were 21 miles left to the beach.
Using this information, we can set up the following equation to find [tex]\( x \)[/tex]:
[tex]\[ \text{Miles traveled} + \text{Miles left} = \text{Total distance} \][/tex]
In mathematical terms, this equation is:
[tex]\[ x + 21 = 46 \][/tex]
So the correct equation to use is:
[tex]\[ 21 + x = 46 \][/tex]
Therefore, the correct answer is:
C. [tex]\( 21 + x = 46 \)[/tex]
