SmarterEd

Aussie Maths & Science Teachers: Save your time with SmarterEd

  • Login
  • Get Help
  • About

Functions, 2ADV EQ-Bank 08

Solve for \(x\), giving your answers in the simplest form  \(a+b\sqrt{c}\)  where \(a, b\) and \(c\) are real:

\(5 x^2-20 x+4=0\)   (2 marks)

--- 6 WORK AREA LINES (style=lined) ---

Show Answers Only

\(x=2 \pm \dfrac{4}{5} \sqrt{5}\)

Show Worked Solution

\(5 x^2-20 x+4=0\)

\(x\) \(=\dfrac{-b \pm \sqrt{b^2-4 a c}}{2 a}\)
  \(=\dfrac{20 \pm \sqrt{20^2-4 \times 5 \times 4}}{2 \times 5}\)
  \(=\dfrac{20 \pm \sqrt{320}}{10}\)
  \(=2 \pm \dfrac{8 \sqrt{5}}{10}\)
  \(=2 \pm \dfrac{4}{5} \sqrt{5}\)

Filed Under: Quadratics and Cubic Functions (Adv-2027) Tagged With: Band 3, smc-6215-10-Quadratics, smc-6215-15-Quadratic Formula

Copyright © 2014–2025 SmarterEd.com.au · Log in