The half-life of a radioactive kind of radium is 11 days . how much will be left after 22 days , if you start with 64 grams of it?

Half- life means after the half life period, only half the original amount remains.

So after 11 days half of 64 grams remain: 64 / 2 = 32 grams,

The after another 11 days, which would be 22 days total ( 11x 2=22) only 32/2 = 16 grams would remain.

to plot points   for x just start at the origin (middle) and go to the left however many times it say(if the number is a positive) if the number is a negative then go right however many times it says if it is 0 go nowhere

now keep you pencil there and go up however many times it says on y(if it is positive) if it is negative then go down however many times it says. if it says 0 go nowhere.

you have just plotted a point! now when you finish plotting all of them connect them with a ruler

plot each point as (-3, 7), (0,4), (3,1), (8,-4)   in the parenthesis on the left of the comma is x and the right is y.