the weight of the substance after 28 years is 8 grams.
<h3>How to determine the amount</h3>
We have that the half life of a substance is defined as the time required for the substance to decrease by half
The formula for calculating the half - life of a material is given as;

Where
- N(t) is final amount
- No is the initial amount = 128 grams
- t1/2 is the half life = 7 years
- t is the time elapsed = 28 years
Substitute into the formula
N(t) = 128 × (0. 5) ^28/ 7
N (t) = 128 × ( 0. 5) ^ 4
N(t) = 128 × 0. 0625
N(t) = 8 grams
Thus, the weight of the substance after 28 years is 8 grams.
Learn more about half life here:
brainly.com/question/26148784
#SPJ1
X=13; do you need the work? Also for future reference symbolab.com is where I get all my answers.
Let me give you a tip use M= y1-y2/x1-x2 to find the slope with to points
Answer:
y=x+3
Step-by-step explanation:
brainleist pls
9d - 5 = 4d + 35
9d (-4d) - 5 (+5) = 4d (-4d) + 35 (+5)
5d = 40
5d/5 = 40/5
d = 8
hope this helps