derive an equation who's coefficients are integers and who's roots are $\frac{1}{2} $ and $\ 7 $ . I'm getting $\ 2x^2-15x+7 $ but the book says $\ 2x^2 +13x-7 $ ... who's right, who's wrong, how do u arrive at the answer?

Question

anonymous · Answer

youre right ant the book is wrong

anonymous · Answer

Saso is always right. :)

sasogeek · Answer

i'm tired of this book and seriously want to get rid of it now but it has so many good review questions with wrong answers :@ i find more wrong answers than right answers it's so bad :@

katrinakaif · Answer

Did you confirm with Wolframalpha or does it not compute these problems?

sasogeek · Answer

i think certain questions don't even require the use of a calculator, not to even speak of wolfram

katrinakaif · Answer

I find it quite hard to believe that the book is inaccurate

sasogeek · Answer

well in ghana you can find such books and :@ i hate it!!!! believe it or not my teachers recommend it because of it's questions, not because of it's answers, sucks :@@@@@@

sasogeek · Answer

some sections are treated well, others, it's just so bad like i said, i find more wrong answers than right ones... at some sections :@@@@@@@@@@@@@@@

katrinakaif · Answer

Ah I see.

anonymous · Answer

kat, the book is inaccurate in this case, the books answer implies the roots to be -7 and 1/2

katrinakaif · Answer

I understand why it is inaccurate but I find it quite hard to believe that books trying to guide students for examinations are inaccurate.

sasogeek · Answer

do so many books have similar typos? i find this one odd

katrinakaif · Answer

Most probably

anonymous · Answer

Okay kat, tell me how I should we approach "this kinds" of problems ;)

bahrom7893 · Answer

It's spelled whose btw

sasogeek · Answer

sorry my mistake lol, thanks for the heads up on that one :)

sasogeek · Answer

ffm kat might not answer u lol, it's "too early" (or too late kat) for her to solve maths

katrinakaif · Answer

I haven't been in bed..my brain feels fried.

anonymous · Answer

you dont' need brain to solve this ...

katrinakaif · Answer

What do you want?

anonymous · Answer

eyes and figures to type ..

amistre64 · Answer

2x^2 +13x - 7

7*2 = 14

14 and 1 subtract to 13

(x+14/2) (x-1/2)

x = -7, 1/2
----------------------

otherwise:

(x+7)(2x+1) = 2x^2 +15x - 7

anonymous · Answer

x^2 - (sum of the roots)x + product of the roots

sasogeek · Answer

roots are 7 and 1/2 => x=1/2 or x=7 =>x-7=0 or2x-1=0 hence (2x-1)(x-7)=0 and 2x^2-15x+7=0 hence expression with 1/2 and 7 as roots is 2x^2-15x+7