Question

Solve quadratic equation 10x^2+x-2=0

Answer 1

`\{-(1)/(2) \} \cup \{(2)/(5)\}`

Explanation:

`10x^2 + x - 2 = 0; \\ a = 10, b = 1, c = -2; \\ D = b^2 - 4ac = 1^2 - 4 * 10 * (-2) = 1 + 80 = 81 = 9^2, > 0; \\ x_(1, 2) = (-b \pm √(D))/(2a) = (-1 \pm √(9^2))/(2 * 10) = (-1 \pm 9)/(20) = \left \ [ {{(-1 - 9)/(20) = -(10)/(20) = -(1)/(2) } \atop {(-1 + 9)/(20) = (8)/(20) = (2)/(5)}} \right.`