Verify the identity.

sin (x + y) - sin (x - y) = 2 cos x sin y

Lin and Tyler are drawing circles. Tyler's circle has twice the diameter of lins circle. Tyler thinks that his circle will have twice the area of Lin's circle as well. Do you agree with Tyler?

A square has been enlarged so that its sides are now three times larger than the original. The area of the original square meter was 11 meters*squared*. What is the area of the square after the enlargement?

6x - 3y + 2z = - 30 6x + 5y=-4 -6z = - 18

A collection of 36 coins consists of nickels, dimes, and quarters. There are three fewer quarters than nickels, and six more dimes than quarters. How many of each kind of coin?

the temperature in Portland, Marine, reached - 3.5ºF one day last winter. Between with two integers does the temperature lie?

Ken read 30 pages of a book on monday and 1/8 of the book on tuesday, he completed the remaining 1/4od the book on wednesday. how many pages are there in the book?

What is the answer to (r-s) 3 r2 if r = - 3 and s = - 4

Mattie uses the discriminant to determine the number of zeros the quadratic equation 0 = 3x2 - 7x + 4 has. Which best describes the discriminant and the number of zeros? The equation has one zero because the discriminant is 1.

Three times the sum of x and seven is greater than it equal to the sum of two x and six

the sum of the digits of a two-digit number is 9. when the digits are reversed, the new number is 9 more than the original number. find the original number. check your answer.