<span>68=-16t2+64t+8
16t2-64t+60=0
4t2-16t+15=0
(2t-5)(2t-3)=0
t=5/2 or 3/2
The object is at 68 feet after 3/2 secs, and returns to 68 feet after another second..</span>
We know that
1 cubic yards equals to--------------> 27 <span>cubic feet
then
</span><span>I apply a rule of three
if </span>1 cubic yards ------------------- 27 ft³
X----------------------------------> 648 ft³
X=648/27=24 cubic yards
the answer is 24 cubic yards
Because the two angles add up to equal 90, you would make an equation set to equal 90. On the other end you add the measures of your angles together because they are adding up to equal 90. This would look like 2x+5+35=90 and you solve from here. Add like terms making it 2x+40=90 then you subtract 40 from both sides making it 2x=50 and then divide by 2 on both sides which leaves you with x=25.
For the first 3 you just have to divide (forget about the square root for now) and then reduce its result by finding two numbers (one of them have to be able to be squared rotted) that multiplied gives the fist result. Then you just have to square root one of the numbers and leave the other one as it is.
For the last 4; you cannot have radicals in the denominator, so you have to multiply both top and bottom by the square root, after that you just reduce.
Hope you understand, if you have any questions please let me know.