How do you quickly solve for a and b in (3x² + a)(2x² + b) type questions on SAT?
How do I do this one asap in case I get something like this on the real sat? It is one of those questions where you have to match the constants in (3x^2+a)(2x^2+b).
13 Answers
You can just graph the relationships as an intersection. If you expand it, we know ab=35 and 3b+2a=31. Treat a and b as x and y. Run it through the graphing cal…
Thank you for this, because all this Desmos regression stuff is like learning another language to me. This is by far the easiest way.
I agree that doing something like this is the superior method. People are a little attached to doing everything with regressions, but it is often a more effecti…
The third way that no one has mentioned is to use the quadratic formula to find a and c. It's fairly quick as well once you get b=(31-2a)/3 and substitute it ba…
The original function is, but what we really want to solve is not. It's a common question where you are given the product of two numbers and the sum of somethin…
If you really want to use regressions, just set x as a list of values so it doesn't mess up the constants.
Why did you enter a list for x?
Because x isn't a constant. It's a variable, so you put in some values for it so Desmos won't mess it up. If x has a restriction, make sure the values apply to …
Yeah, or you can just set x=random(10) and it will pick 10 random values for you automatically.
Provided how often people ask to solve it, we probably won't even see this exact question on the test.
Murphy's law. It's probably just unlikely to show up since it's asked about so much, meaning many people will learn how to solve it extremely fast.
How do you know it won't show up?
Time is the biggest issue. I averaged a 1520 but got a 1420 on June. I usually feel like I can get an 800 on Math, but I just ran out of time. I really hope Col…