1.

if alpha and beeta are the zero of the polynomial p(x)=3x2--12x++15 find the value of alpha square ++beeta square​

Answer»

Solution :

\bf{\green{\underline{\underline{\bf{Given\::}}}}}

If α and β are the ZEROES of the polynomial p(x) = 3x² - 12X + 15.

\bf{\green{\underline{\underline{\bf{To\:find\::}}}}}

The value of α² + β².

\bf{\green{\underline{\underline{\bf{Explanation\::}}}}}

We have quadratic polynomial as we compared with ax² + bx + c = 0;

  • a = 3
  • b = -12
  • c = 15

\bf{\orange{\underline{\underline{\mathcal{SUM\:OF\:THE\:ZEROES\::}}}}}

\mapsto\sf{\alpha +\beta =\dfrac{-b}{a} =\dfrac{Coefficient\:of\:(x)^{2} }{Coefficient\:of\:x} }\\\\\\\mapsto\sf{\alpha +\beta =\dfrac{-(-12)}{3} }\\\\\\\mapsto\sf{\alpha +\beta =\cancel{\dfrac{12}{3}} }\\\\\\\mapsto\sf{\red{\alpha +\beta =4}}

\bf{\orange{\underline{\underline{\mathcal{PRODUCT\:OF\:THE\:ZEROES\::}}}}}

\mapsto\sf{\alpha \times \beta =\dfrac{c}{a} =\dfrac{Constant\:term }{Coefficient\:of\:x} }\\\\\\\mapsto\sf{\alpha \times \beta =\dfrac{15}{3} }\\\\\\\mapsto\sf{\alpha \times \beta =\cancel{\dfrac{15}{3}} }\\\\\\\mapsto\sf{\red{\alpha \times \beta =5}}

Now;

\mapsto\sf{\alpha^{2}  +\beta ^{2} =(\alpha +\beta)^{2}  -2\alpha \beta }\\\\\mapsto\sf{\alpha^{2}  +\beta^{2}  =(4 )^{2} -2(5) }\\\\\mapsto\sf{\alpha^{2} +\beta^{2} =16 -10}\\\\\mapsto\alpha^{2} +\beta ^{2}=16-10}\\ \\\mapsto\sf{\orange{\alpha^{2}+ \beta ^{2} =6}}



Discussion

No Comment Found

Related InterviewSolutions