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1. c) α = 5, β = -¾

Use the method shown in the above example to write down the equations whose roots are: (α+β and αβ)

I get...
α+β= 5/4
αβ= -15/4

((times by 4 to remove the fractions))

4x2 -17x - 15 = 0

What did I do wrong?
2. (Original post by ckfeister)
c) α = 5, β = -¾

Use the method shown in the above example to write down the equations whose roots are: (α+β and αβ)

I get...
α+β= 5/4
αβ= -15/4

((times by 4 to remove the fractions))

4x2 -17x - 15 = 0

What did I do wrong?
3. On the next question,
α = -3, β = -4

I get

α+β= -7
αβ= 12

x2 + 7x + 12 = 0

What did I do wrong here?
4. (Original post by Mr M)
5. (Original post by ckfeister)
How do I do then?
6. (Original post by Mr M)
I noticed after looking at it, I have dyslexic so I can't find these on own for some reason... also what about the other question? I got -7x not +7x (question is above)
7. (Original post by ckfeister)
what about the other question? I got -7x not +7x (question is above)
This is the third time you have had the same problem at this final step on different threads so I don't think you are getting it. You always need to change the sign of the sum.

It's because (note the negative sign).
8. (Original post by Mr M)
This is the third time you have had the same problem at this final step on different threads so I don't think you are getting it. You always need to change the sign of the sum.

It's because (note the negative sign).
So even when shown on I still use negative sign? I know
9. (Original post by ckfeister)
So even when shown on I still use negative sign? I know
To form the quadratic equation do this:

(sum of roots) (product of roots)

This will always give you the right answer.
10. (Original post by Mr M)
To form the quadratic equation do this:

(sum of roots) (product of roots)

This will always give you the right answer.
thx
11. P = FV
( -93 1/2 )

How comes I got -42 1/2 on bottom?
(27*-2) + (5*17) = 31
(0*-2) + (-5 1/2*17) = -42.5
??

12. (Original post by ckfeister)
P = FV
( -93 1/2 )

How comes I got -42 1/2 on bottom?
(27*-2) + (5*17) = 31
(0*-2) + (-5 1/2*17) = -42.5
??

It's your dyslexia again. You have read a five as a two.
13. (Original post by Mr M)
It's your dyslexia again. You have read a five as a two.
Nevermind found it, thx again...
14. (Original post by ckfeister)
Where?
Negative five point five times seventeen.

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