Every 56 seconds, the radioactive substance is divided in half.
224 / 56 = 4
We need to cut the substance in half 4 times.
896 / 2 = 448
448 / 2 = 224
224 / 2 = 112
112 / 2 = 56
After 224 seconds, there will be 56 grams of the radioactive substance left over
<span>2x + 4y = 36
3x - 4y = -6
--------------add
5x = 30
x = 6
</span>2x+4y=36
2(6)+4y=36
12 + 4y = 36
4y = 24
y = 6
answer
<span>(6, 6) is a solution of equations
</span><span>(4,7) is NOT a solution of equations</span>
A because 12*4=48 and 32*4=128
