You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
solving but not getting the answer
- Thread starter algebra
- Start date
Is this supposed to bex2 − 21.75x = −15.75
x2 − 21.75x = −15.75
If so, rearrange to
x2 − 21.75x +15.75 = 0
and use the quadratic formula (eyeballing looks like about 2.5 and 19)
Is this supposed to be
x2 − 21.75x = −15.75
If so, rearrange to
x2 − 21.75x +15.75 = 0
and use the quadratic formula (eyeballing looks like about 2.5 and 19)
cant use formula
has to be solved fairly quickly
did the box method but takes too long
cant use formula
has to be solved fairly quickly
did the box method but takes too long
oh sorry yes it is x square
Can you try an iterative methodcant use formula
has to be solved fairly quickly
did the box method but takes too long
\(\displaystyle x_{i+1} = x_i - \dfrac{x_i^2 − 21.75 x_i + 15.75}{2 x_i − 21.75}\)
For the two different roots start with my two guess above although they are not all that good. It shouldn't take more than 3 or 4 iterates.
Multiply by 4:
4x^2 - 87x + 63 = 0
Factor:
(4x - 3)(? - ?) = 0
Finish it...
(4x - 3) is only one of many potential factors to consider for the first factor. Others are:
(4x - 1), (4x - 7), (4x - 9), (4x - 21), (4x - 63), (2x - 1), (2x - 3), etc.
Not if you know the answer(4x - 3) is only one of many potential factors to consider for the first factor. Others are:
(4x - 1), (4x - 7), (4x - 9), (4x - 21), (4x - 63), (2x - 1), (2x - 3), etc.
Not if you know the answer
The student can't read Denis's mind. Denis revealed no reason as to why he chose that
factor for the student (if it does work).
And if it's a case of the tutor thinking/working "I happen to know this partial combination
of factors that works," then that part isn't a help to the student.