The half life of a chemical element substance is 16 days, How long will it takes for the substance to decay from 120mg to 2 mg

the answer is b

i dony know

step-by-step explanation:

i think it is everything has to equal 180 so, if i correct 4=c. 6=d. 8=a. 7=b. and the last question would be c. because they are parallel lines and they are congruent.

step-by-step explanation:

the reason everything has to equal to 180 is because that is how it works. i'm guessing that is its rule. 4 and 8 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 6 and 7 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 60+60 is 180. so, now you have your answer

answer: c

(2, -4)

goes 7 to the

(9, 4)

easy