A 70 kg jogger has a Kinetic Energy of 680 joules. What is his velocity?

Pls! does anybody know a shortcut for answering these types of questions in the future?

Its due ! write an equation in which the quadratic expression 2x^2-2x 12 equals 0. show the expression in factored form and explain what your solutions mean for the equation. show your work.

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?