Answer:
28 feet or greater
Explanation:
To begin, we know that the quicksand is about 75 feet wide, meaning that the large tree branch must be 75 feet or longer in order for you to walk across it.
You can rewrite the equation to find the answer like this: 75 = 2x + 19, and to use some basic algebra you can subtract 19 on both sides to isolate the variable.
Leaving you with: 56 = 2x, now that you have a value on one side and your variable on the other, you can divide both sides by 2 to simplify the equation and get your answer.
Your final answer is 56 / 2 = x or 28 = x, meaning that the tree branch must be 28 feet or longer in order for you to safely walk a cross it.
Hope this helps, let me know if you have any additional inquiries.