Why is there no middle term in the product(a-b)(a+b)?

If 1/2+2/5s=s-3/4,what is the value of s? a. s=3/4 b. s=25/12 c. s=-25/12 d. s=-3/4

Let event a = you roll an even number on the first cube.let event b = you roll a 6 on the second cube.are the events independent or dependent? why?

‼️‼️‼️‼️‼️the pressure exerted on the walls of a container by a gas enclosed within it is directly proportional to the temperature of the gas. if the pressure is 6 pounds per square inch when the temperature is 440 f, find the pressure exerted when the temperature of the gas is 380°f. (show work)