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MATH HELP!!! 100PTS!!!

Let p(x)=2x−4 and r(x)=6x−1/9x+1.
Solve p(x)=r(x) for x exactly. If there is more than one answer, enter your exact solution(s) in a comma separated list.

Respuesta :

Answer:

[tex]x =\dfrac{20 +\sqrt{454}}{18}, \quad \dfrac{20 -\sqrt{454}}{18}[/tex]

Step-by-step explanation:

Given functions:

  [tex]p(x)=2x-4[/tex]

  [tex]r(x)=\dfrac{6x-1}{9x+1}[/tex]

Solve for p(x) = r(x):

[tex]\begin{aligned}p(x) & = r(x)\\\implies 2x-4 & = \dfrac{6x-1}{9x+1}\\(2x-4)(9x+1)&=6x-1\\18x^2+2x-36x-4&=6x-1\\18x^2-40x-3&=0\end{aligned}[/tex]

As the found quadratic equation cannot be factored, use the Quadratic Formula to solve for x:

Quadratic Formula

[tex]x=\dfrac{-b \pm \sqrt{b^2-4ac} }{2a}\quad\textsf{when }\:ax^2+bx+c=0[/tex]

Therefore:

[tex]a=18, \quad b=-40, \quad c=-3[/tex]

Substitute the values of a, b and c into the quadratic formula and solve for x:

[tex]\begin{aligned}\implies x & =\dfrac{-(-40) \pm \sqrt{(-40)^2-4(18)(-3)} }{2(18)}\\\\& =\dfrac{40 \pm \sqrt{1816}}{36}\\\\& =\dfrac{40 \pm \sqrt{4 \cdot 454}}{36}\\\\& =\dfrac{40 \pm \sqrt{4}\sqrt{454}}{36}\\\\& =\dfrac{40 \pm2\sqrt{454}}{36}\\\\& =\dfrac{20 \pm\sqrt{454}}{18}\end{aligned}[/tex]

Therefore, the solutions are:

[tex]x =\dfrac{20 +\sqrt{454}}{18}, \quad \dfrac{20 -\sqrt{454}}{18}[/tex]

Learn more about quadratic equations here:

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