To represent the problem with an equation, let's define \( x \) as the height that Cheyenne’s brother climbs.
According to the problem, Cheyenne climbs 468 feet, which is 129 feet more than what her brother climbs. This can be expressed as:
\[ 468 = x + 129 \]
This describes that Cheyenne's climb (468 feet) is equal to her brother's climb (x feet) plus the additional 129 feet.
So, the correct form of the equation, based on the given responses, is:
\[ x + 129 = 468 \]
Thus, the answer is: x + 129 = 468.