Problems with Quadratic Equations: A Review (GRE Quantitiative/Math Practice)

So listen, you could just plug in 3 for x. It is known to be a solution, which means you are allowed to substitute it. This leaves you with the equation:

(3)^2 +k(3) - 6 = 0

Try it; the solution to this one-variable equation is -1.

This method is obviously superior to the one I outlined here.

BUT, this is not always a possibility and you will often have to solve a real quadratic as I did in my review. You do NOT want to go into the GRE without the ability to solve a quadratic or identify the different steps that come out from the process, so please learn what you can from the video! You might thank me for looking at this the "advanced" way. Cheers!

One of the roots of the equation x^2 + kx - 6 is 3, and k is a constant.

[StephanPichardo]

So listen, you could just plug in 3 for x. It is known to be a solution, which means you are allowed to substitute it. This leaves you with the equation:

(3)^2 +k(3) - 6 = 0

Try it; the solution to this one-variable equation is -1.

This method is obviously superior to the one I outlined here.

BUT, this is not always a possibility and you will often have to solve a real quadratic as I did in my review. You do NOT want to go into the GRE without the ability to solve a quadratic or identify the different steps that come out from the process, so please learn what you can from the video! You might thank me for looking at this the "advanced" way. Cheers!