In doing this you can use the factoring method to do this faster. Start by dividing both sides by two to simplify the equation. X^2 now equals 100.
You can move 100 to the other side of the equation so that x^2-100=0. You can now factor and solve using the zero product property.
x^2-100=0
(x+10)(x-10) = 0
x equals 10 and -10.
I think the answer is 33510.32in³
Volume for a cone is 1/3 pi * r^2*h, where r is radius and h is height. We have diameter = 1/2 radius. Thus, radius = 1.5in. We also have volume is 12 in. Using formula for volume of a cone and plugging in what we know, we have 12 = 1/3*pi*(1.5)^2*h, were solving for h. To get, h= (12*3)/(pi*(1.5)^2), which is approximately 5.0931in, 5 inches
It cannot be simplified more than that. hope this helps!
7. 335*0.2=67
8. 4.5/0.6=7.5
9. A
Hope this helps!