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# easiest method to solve this watch

1. Easiest method to solve this?

Thanks.
2. Try dividing by t (or is it l, cant seem to click on image). Should be able to see a recognisinle type of equation then. You should try substiution.

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3. (Original post by alwayslast)
Try dividing by t (or is it l, cant seem to click on image). Should be able to see a recognisinle type of equation then. You should try substiution.

Posted from TSR Mobile
the mark seem suggests factoring to get

but I am not sure how they do this
4. (Original post by upthegunners)

Easiest method to solve this?

Thanks.
As before divide by t. Then observe that this is a hidden quadratic
Hint:
Spoiler:
Show
Solve for t^2 and hence for t.
5. (Original post by upthegunners)

Easiest method to solve this?

Thanks.
t=0

or

3t^4-4t^2-15=0

3t^4-4t^2=15

t^2(3t^2-4)=15

i dunno really
6. (Original post by joostan)
As before divide by t. Then observe that this is a hidden quadratic
Hint:
Spoiler:
Show
Solve for t^2 and hence for t.
no u do no divide by t as u lose a solution t=0

do not listen to this op
7. (Original post by upthegunners)
the mark seem suggests factoring to get

but I am not sure how they do this
It's how you factorise any other quadratic eqation.
8. (Original post by joostan)
As before divide by t. Then observe that this is a hidden quadratic
Hint:
Spoiler:
Show
Solve for t^2 and hence for t.
is letting say and solving a good idea? Then just subbing back in?
9. t(3t^4 - 4t^2 - 15)=0

3t^4 - 4t^2 - 15=0

t^2 = x

3x^2 - 4x - 15=0
(3x+5)(x-3) = 0
So, x= -5/3 or 3

therefore,
t^2= 3
t=Sqrt 3
10. (Original post by Student#123)
no u do no divide by t as u lose a solution t=0

do not listen to this op
The loss of the solution t = 0 only occurs if you don't write it down. It is the obvious solution, once written down, it's not a problem and you're left with a hidden quadratic.
11. (Original post by upthegunners)
is letting say and solving a good idea? Then just subbing back in?
Yes, don't forget that when you solve for t that there is a solution where t = 0
12. Let x = t^2 then solve as a quadratic

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