what algebraic expression must be added to the sum of 3x^2+4x+8and 2x^2-6x+3 to give 9x^2-2x-5 as the result

Element 17 is chlorine it is a group 7 element(halogen) and belongs to period 3 of the periodic table

Idon’t know the answer to this

Period is the time it takes for one “cycle” to complete. in the parent sine function, period is 2*pi since sin(0) = 0, sin(pi/2) = 1, sin(pi) = 0, sin(3pi/2) = -1, and sin(2pi) = 0. at that point, the sequence repeats itself. i’m not sure if your graph is similar to the sine function since you didn’t provide a picture, but you can find the period by looking at a graph.