(6x 2 - 4x + 11) + ( 4 - x 2 - 3x)

Which of the following is correct interpretation of the expression -4+13

In the sixth grade 13 out of 20 students have a dog if there are 152 sixth grade students how many of them have a dog

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?