Hello, I know you’ve already solved practise test 2, section 4 question 29 (by either using your graphic calculator or by looking at the equation of a parabola) but how would you use backsolving? Lets say I try in option C and im getting y as 3 (which means my equations do NOT have 2 real solutions), how do I know whether to try out option B or D next?

Thank you so much!

You wouldn’t really know whether to try B or D next without knowing that you’re playing with whether the parabola opens up or down and its *y*-intercept when you change *a* and *b*, respectively. This is important, though: don’t waste more than a couple seconds trying to figure out which way to go! If you don’t know which choice to try next right away, pick any one. If you’re backsolving simply by changing a graph on your calculator, it shouldn’t take more than a couple seconds to try each choice until one works.