Which products result in a difference of squares? check all that apply.

(x – y)(y – x)
(6 – y)(6 – y)
(3 + xz)(–3 + xz)
(y2 – xy)(y2 + xy)
(25x – 7y)(–7y + 25x)
(64y2 + x2)(–x2 + 64y2)

Solve the given system of equations. 2y= -x+9 , 3x-6= -15

The means and mean absolute deviations of the individual times of members on two 4x400-meter relay track teams are shown in the table below. means and mean absolute deviations of individual times of members of 4x400-meter relay track teams team a team b mean 59.32 s 59.1 s mean absolute deviation 1.5 s 245 what percent of team b's mean absolute deviation is the difference in the means? 9% 15% 25% 65%

Ibeg you to me 20. a reaction produces 4.93 l of oxygen, but was supposed to produce 1 mol of oxygen. what is the percent yield?