What is the factored form of the expression t^2-81 a. ( t + 9 ) ( t - 9 ) b. ( t + 81 ) ( t - 81 ) c. ( t + 9 )^2 d. ( t - 9 )^2 i believe it's a, but i'm not sure. .

Astudent has created the give circuit diagram. it consists of a battery, a resistor, and a light bulb. in one minute, 1.2c of charge flows through the resistor. how much charge flows through the light bulb in one minute?