Element X is a radioactive isotope such that every sixty nine years, its mass decreases by half. Given that the initial mass of a sample of Element X is 20 grams, how much of the element would remain after 30 years, to the nearest whole number?

1) the property is   ixi = a ⇔x = a   o x = -a

4(x-5)+3= 15⇒4x-20+3 = 15⇒4x-17= 15⇒4x = 15+17⇒4x = 32⇒x =32/4= 8

4(x-5) +3= -15⇒4x-20 +3 = -15⇒4x-17= -15⇒4x =-15+17⇒4x = 2⇒x =2/4= 1/2

the values are x =8 and x = 0,5

we need to see the graph to know but

strong positive is if it is going up from left to right in a straight diagonal line (like this /)

strong negative is the same but from right to left (like this \)

weak negative is the same as strong negative but its more straight line still right to left

and weak positive is the same as strong positive but more a straight line still left to right though.