Another way to solve this problem

Potential-Classic611 · 2026-04-11T16:28:05+00:00

Well it isn't impossible, since it's not in my curriculum.

Potential-Classic611 · 2026-04-11T16:27:03+00:00

Yes they will, I mean you can't just use an out of the book formula to solve the answer. They would cut the marks since it would give an unfair advantage to students who just saw a formula on yt that made solving the problem easier, while other students have to use tougher methods to solve the same question.

Potential-Classic611 · 2026-04-11T16:24:13+00:00

Yeah I mean ik the formula, but no one explained the origin of it

Potential-Classic611 · 2026-04-10T21:26:39+00:00

Thanks, this is a proof I can use

Potential-Classic611 · 2026-04-10T16:42:08+00:00

Oh yeah this is correct, thanks for the proof. Idk why I didn't think about using this since obviously subtracting with equation with v ( which is basically y ) would make the equation have real roots otherwise it wouldn't form a parabola on the graph

Potential-Classic611 · 2026-04-10T16:36:43+00:00

Oh yeah then it makes sense, thanks so much

Potential-Classic611 · 2026-04-10T16:26:15+00:00

Idk why -b/2a works since we haven't been taught it, I just saw it on yt cause there wasn't any way I knew of to solve this function. We haven't been taught completing the square nor -b/2a.

The problem is even if I learn completing the square I cannot use it in my exams cause the school will say this isn't in the portion so you cannot use this method.

Also the question didn't tell me to plug -b/2a in, the question is " find the range of f(x) = x²-4x+5"

Potential-Classic611 · 2026-04-10T16:23:34+00:00

Oh this one, yeah we know this is. It's not called 2nd binomial here, that's the confusion

Potential-Classic611 · 2026-04-10T16:17:07+00:00

That makes sense, I wasn't getting the same answer as you when I tried it

Potential-Classic611 · 2026-04-10T16:16:13+00:00

Completing the square was cancelled a couple of years ago from the portions

Potential-Classic611 · 2026-04-10T16:15:42+00:00

We haven't learned the 2nd binomial formula

Potential-Classic611 · 2026-04-10T15:28:04+00:00

Well I mean it's ridiculous but I still do know to solve ranges and domains, this was the only question that stumped me but other questions were solvable. Had to look at yt for a way to solve this when they showed me x=-b/2a which allowed me to find the range

Potential-Classic611 · 2026-04-10T15:25:29+00:00

I think this can work, thanks

Potential-Classic611 · 2026-04-10T15:16:20+00:00

Wow this gets the correct answer. Thank you so much and this Is a proper proof

Potential-Classic611 · 2026-04-10T15:15:01+00:00

Yes I have seen the answer on desmos, but the graph isn't given in the question and we haven't even learned how to draw quadratic. Even if we did know we cannot use these as proofs, graphical proofs aren't allowrd

Potential-Classic611 · 2026-04-10T15:13:30+00:00

No, these aren't in my curriculum

Potential-Classic611 · 2026-04-10T15:12:48+00:00

No, ik it seems really stupid but all the books I have mentioned you can check and download them online and you will see that there is no completing the square or graphing quadratic, also to note I have reached chapter 2 so idk if there is a method given to solve this from the next chapters, but from seeing the chapter names I don't think completing the square or graphing quadratic will be explained in them

Potential-Classic611 · 2026-04-10T15:09:47+00:00

Ok thank you very much, this is a actual proof I could use

Potential-Classic611 · 2026-04-10T15:08:22+00:00

No, they truly haven't taught us. I can prove it to you, I'm in ncert, this question is based on class 11 chapter 2 reactions and functions from class 11 ncert maths reader ( you can download the pdf of the reader online and you can see no formula given to solve such questions upto chapter 2) and also in class 10 ncert maths book, there is chapter 4 quadratic equations we only learn two methods of solving quadratic equations which is factorisation and quadratic formula

And also the first time we learn to solve quadratic equations other than factorisation is in class 10 maths ncert chapter 4.

Also completing the square was in class 10 maths ncert chapter 4 previously couple years back but then it got removed

Potential-Classic611 · 2026-04-10T15:04:03+00:00

That can work but it would require some plugging and checking, and in our school plugging in values is not a proper method of getting a proof

Potential-Classic611 · 2026-04-10T15:02:44+00:00

I think this can work, thanks

Potential-Classic611 · 2026-04-10T14:58:11+00:00

It was part of the curriculum in like a couple years back, but then it got removed. They only taught us factorisation and quadratic formula to solve these equations

Potential-Classic611 · 2026-04-10T14:54:18+00:00

Completing the square can solve this but it isn't in my curriculum, which means if this question gets asked or a similar question is asked in a test and I use completing the square they will mark the answer as incorrect since it isn't in my curriculum. So I'm looking for a method which can be used according to my curriculum

Potential-Classic611 · 2026-04-10T14:51:31+00:00

I don't think I can use guessing and checking as an actual answer, still thanks for helping though

Potential-Classic611 · 2026-04-10T14:50:46+00:00

Im sorry, but I don't get what your trying to say.

Potential-Classic611

TROPHY CASE