by Elizabeth Contrera
(Salinas, California, United States)

x^2 + 6x = 9

Check the work by substituting your solutions for x into the original equation

 Dec 01, 2011 Quadratic Equation by: Staff Question: by Elizabeth Contrera (Salinas, California, United States) x^2+6x=9 Answer: x² + 6x = 9 You can solve this equation for x in a number of different ways. Using the quadratic formula is probably the fastest way: ax² + bx + c = 0 x = [-b ± √(b² - 4ac)]/(2a) Rearrange your equation so that it is in the standard format for a quadratic equation (ax² + bx + c = 0). x² + 6x = 9 x² + 6x - 9 = 9 – 9 x² + 6x - 9 = 0 x = unknown a = 1 b = 6 c = -9 x = [-6 ± √(6² - 4*1*(-9))]/(2*1) x = [-6 ± √(36 + 36)]/(2) x = [-6 ± √(72)]/(2) x = [-6 ± √(2*2²*3²)]/(2) x = [-6 ± √(2²)*√(3²)*√(2)]/(2) x = [-6 ± 2*3*√(2)]/(2) x = [-6 ± 6*√(2)]/(2) x = -6/2 ± [6*√(2)]/2 x = -3 ± 3*√(2) x₁ = -3 + 3*√(2) x₁ ≈ 1.2426406871193 x₂ = -3 - 3*√(2) x₂ ≈ -7.2426406871193 the final answer is: x ∈{-3 - 3*√(2), -3 + 3*√(2)} or x ∈{-7.2426406871193, 1.2426406871193} Thanks for writing. Staff www.solving-math-problems.com