Answer to Question #132339 in Algebra for Timmy

Question

    Solve the equation; x² - 8x + 7 = 0 using the Quadratic Formula

Answer 1

Solutions of the quadratic equation

. $ax^{2}+bx+c=0,\; a\neq0\;\;are- \\ \\ x =\dfrac{-b \plusmn \sqrt{b^2-4ac}}{2a} \\ \\ Here, we\:need\:to\:solve- \\ x^{2}-8x+7=0 \\ i.e., a=1, b=-8,c=7 \\ so, x=\dfrac{-(-8)\plusmn\sqrt{(-8)^{2}-4(1)(7)}}{2(1)} \\ \implies x = \dfrac{8 \plusmn \sqrt{64-28}}{2}$

$\implies x = \dfrac{8 \plusmn 6}{2} =7,1$