Which equation is incorrect?

Simplify sin (2x+7y) + sin (2x-7y)

Four numbers have a median of 4, a mean of 5 and a range of 9. The numbers are not integers. What could they be?

How do you write a unit rate for this situation? $28 saved in 4 weeks

Solve the system by linear combination. Show all your work. 9x+5y=35 -2x-5y=0

You have a $25 gift card for a bagel shop. A bagel cost $1.25 write a equation that gives the amount (in dollars) that remains on the card as a function of the total number of bagels you have purchased so far.

Lisa bought five CDs from the store. The price of each CD was the same. After she bought the CDs, her account balance showed a change of - $64.95. What would have been the change to Lisa's account balance had she only bought one CD from the store?

how do i add this 9 7/8 + 6 5/8 + 3 3/8

The displacement, d, in millimeters of a tuning fork as a function of time, t, in seconds can be modeled with the equation d = 0.6 sin (3520rt). What is the frequency of the tuning fork? A, 1/3520 Hz B. 1/1760 Hz C. 1760 Hz D. 3520 Hz

4x-10y=-16 and - 7x+20y=23 elimination

At the beginning of the year 2002, Sarah put $250 in a savings account. The bank agrees to pay Sarah 3% interest on her total savings at the end of each year including the interest added to the account.