You found $6.60 on the ground at school, all in nickels, dimes, and quarters. you have twice as many quarters as dimes 42 coins in all. how many of each type of coin do you have?

Emma will roll two number cubes labeled 1 through 6. she will record the sum of the two numbers after each roll. she will roll the two cubes 540 times. how many times should emma expect the sum to equal 5?

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?

Could somebody me with this radical simplification?