The formula to find density is Mass/Volume
We have
Density =

Volume =

Hence
Mass = 7.8×10504 = 81931.2 gram
U=(x+2)
u^2+5u-6=0
C is answer
I think 517.26
I did 10 times 3^2 (9) it equals 90. Then 90 times 3.14 and got 282.74. Then did 800- 282.74 and got 517.26
So basically you want to isolate only one of the variable on one side so
y=-9+x^2
add 9 to both sides
y+9=x^2
square root both sides

x=