1.

If a and b are zero of a quadratic polynomial x²-6x+1 then value of (1/a+1/b-ab ) is

Answer»

\blue{\bold{\underline{\underline{Answer:}}}}

\green{\tt{\therefore{\frac{1}{a}  +  \frac{1}{b}  - ab = 5 }}}\\

\orange{\bold{\underline{\underline{Step-by-step\:explanation:}}}}

\green{\underline \bold{<klux>GIVEN</klux>: }} \\  \tt:  \implies  {x}^{2} - 6x +1 = 0 \\\\ \tt:\implies a\:and\:b\:are\:zeroes \\\\ \red{\underline \bold{To \: Find: }} \\  \tt:   \implies \frac{1}{a}+\frac{1}{b}-ab= ?

ACCORDING to given QUESTION :

\tt:  \implies  {x}^{2}  - 6x + 1 = 0 \\  \\  \tt \circ \: a = 1 \\  \\ \tt \circ \: b =  - 6 \\  \\ \tt \circ \: c = 1 \\  \\  \bold{For \: finding \: value} \\  \tt:  \implies  \frac{1}{a}  +  \frac{1}{b}  - ab \\  \\  \tt:  \implies  \frac{b + a -( ab)^{2} }{ab}  \\  \\ \tt:  \implies  \frac{a + b -  {(ab)}^{2} }{ab} -  -  -  -   - (1)  \\  \\  \bold{For \: sum \: of \: zeroes} \\  \tt:  \implies sum \: of \: zeroes =  \frac{ - b}{a}  \\  \\ \tt:  \implies a + b =  \frac{ - ( - 6)}{1}  \\  \\  \green{\tt:  \implies a + b= 6} \\  \\  \bold{For \: product \: of \: zeroes} \\ \tt:  \implies product \: of \: zeroes = \frac{c}{a}  \\  \\ \tt:  \implies ab =  \frac{1}{1}  \\  \\  \green{\tt:  \implies ab  = 1}\\  \\  \text{Putting \: given \: values \: in \:  (1)} \\ \tt:  \implies   \frac{a + b -  {(ab)}^{2} }{ab}  \\  \\ \tt:  \implies  \frac{6  -  {1}^{2} }{1}  \\  \\ \tt:  \implies  \frac{6 - 1}{1}  \\  \\  \green{\tt:  \implies 5} \\  \\   \green{\tt \therefore  \frac{1}{a}  +  \frac{1}{b}  - ab = 5}



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