how do you do this
2x^2+5x-7
step by step?
what is the first step?

You solve it the same way as the previous problem you posted: https://www.askmehelpdesk.com/math-sciences/how-do-do-step-step-670751.html

Ik but how do u know when u have 2 use the quadratic formula

Well, I assumed that you wanted to solve for x given 2x^2-5x+7=0. You can always apply the quadratic equation to such problems to find the solutions for x. If that's not what the question is, please clarify.