Answer:68.2
Step-by-step explanation:
cos6=71/EF
cos6= 0.960170286650366
0.960170286650366= 71/EF
0.960170286650366*71=EF
EF= 68.2
6+3x = 2(2 + x)
First we will need to open the parenthesis by multiplying the number that’s in front of them:
6+3x=4+2x
Now we need to separate the numbers from the X. By subtracting 2x from both sides:
6+3x=4+2x
-2x -2x
————————
6+x=4
Now we subtract 6 from both sides.
6+x=4
-6 -6
—————
X = -2
The formula for half-life is:

A is the amount remaining, P is the initial amount, t is the time that has passed, and h is the half-life of the substance. Plug in the values that you know and solve:

Rounded to the nearest whole number, the density of the substance was about 13<span>mg / cm².</span>
3+x=23t therefore the answer should be D