IDNLearn.com is the place where your questions are met with thoughtful and precise answers. Join our knowledgeable community and get detailed, reliable answers to all your questions.

7a) The roots of the equation 4x^2 - 7x - 1 = 0 are G and H. Evaluate G^2+ H^2B) Write the equation of a quadratic with integer coefficients whose solutions are G^2 and H^2.Pls see the pic for more detail.

7a The Roots Of The Equation 4x2 7x 1 0 Are G And H Evaluate G2 H2B Write The Equation Of A Quadratic With Integer Coefficients Whose Solutions Are G2 And H2Pls class=

Sagot :

Given:

[tex]4x^2-7x-1=0[/tex]

Solve:

Quadratic formula:

[tex]x=\frac{-b\pm\sqrt[]{b^2-4ac}}{2a}[/tex]

Where,

[tex]ax^2+bx+c=0[/tex]

Compaire the equation then:

[tex]\begin{gathered} ax^2+bx+c=0 \\ 4x^2-7x-1=0 \\ a=4,b=-7,c=-1 \end{gathered}[/tex]

So roots of equation is:

[tex]\begin{gathered} x=\frac{-(-7)\pm\sqrt[]{(-7)^2-4(4)(-1)}}{2(4)} \\ x=\frac{7\pm\sqrt[]{49+16}}{8} \\ x=\frac{7\pm\sqrt[]{65}}{8} \end{gathered}[/tex]

So value of G and H is:

[tex]\begin{gathered} G=\frac{7+\sqrt[]{65}}{8};H=\frac{7-\sqrt[]{65}}{8} \\ G=\frac{7}{8}+\frac{\sqrt[]{65}}{8};H=\frac{7}{8}-\frac{\sqrt[]{65}}{8} \end{gathered}[/tex]

So:

[tex]\begin{gathered} =G^2+H^2 \\ =(\frac{7}{8}+\frac{\sqrt[]{65}}{8})^2+(\frac{7}{8}-\frac{\sqrt[]{65}}{8})^2 \\ =(\frac{7}{8})^2+(\frac{\sqrt[]{65}}{8})^2+2(\frac{7}{8})(\frac{\sqrt[]{65}}{8})+(\frac{7}{8})^2+(\frac{\sqrt[]{65}}{8})^2-2(\frac{7}{8})(\frac{\sqrt[]{65}}{8}) \\ =2(\frac{49}{64}+\frac{65}{64}) \\ =2(\frac{114}{64}) \\ =\frac{114}{32} \\ =3.5625 \end{gathered}[/tex]

(B)

If roots is a and b the equation is:

[tex]x^2-(a+b)x+ab=0[/tex]

Then equation is:

[tex]G^2+H^2=3.5625[/tex]

[tex]\begin{gathered} G^2H^2=(\frac{7}{8}+\frac{\sqrt[]{65}}{8})^2(\frac{7}{8}-\frac{\sqrt[]{65}}{8})^2 \\ =(0.875+1.00778)^2(0.875-1.00778)^2 \\ =(3.54486)(0.01763) \\ =0.0624 \end{gathered}[/tex]

So equation is:

[tex]x^2-3.5625x+0.0624[/tex]