If x-y=10 and x+y=20 what is the answer for x^2-y^2?

The Earth is said to be 4,540,000,000 years old. Estimate the age of the earth by writing it in the form of a single digit times an integer power of 10.

What is the value of - 8 (17-12)

Write the expressions for 3 consecutive numbers. hint: the first number is x

The top of a ladder rest at a height of 15 feet against the side of a house. If the base of a ladder is 6 ft from the house what is the length of the ladder? round to the nearest foot.

Is it always, sometimes, or never possible for the mean, median, and mode to be equal? Justify your reasoning.

I have done a math equation for school and i forgot if i could leave a inproper fraction as my answer or if its a fraction i can reduce should i or should i not

Enter the value of n so that the expression (-y + 5) + (7y - 9) is equivalent to (ny - 4)

The heavyweight weight class in high school wrestling is from no less than 195lb and a maximum 285 LB write two inequalities to represent this range

A shose box measures 15in. by 7in. by 4 an half

Write the equation or inequality : in order to take honors level math, Lisa must have an average of 85 on her math tests. Her scores so far are 85, 70, and 98. What is the minimum score Lisa needs on the fourth test to get into honors math class?