Help algebra 2...quadratic equation standard form/ and checking problem/solution

how do i write these quadaratic equations in standard form...i know the equation/formula but it doesn't help geez...

-x^2=15
2x-x^2=1


And how do i check the solutions for this problem -x^2-2x+3=0 since we had to identify the roots of the quadratic equation...

thanks a lot..

 

I literally just did this in my math class as well. Not sure on the first part, for the second part I just plugged in the answer till it worked. Because our tests were multiple choice it made it very easy.

 

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For the second one, you foil and get 2 answers in ()'s. After you have the two answers you should set both of them to 0, and solve for X in both equations.

Then I believe that is your answer. Not 100%, I did this so long ago I forgot some, and for the first one uhh just put it in standard form? I don't understand the trouble on that one.

 

omg your fucking lucky...my teacher sucks donkey balls...each of our assignments are worth 6 points max...even if there is 100 problems he only grades 6 so max you can get is 6/6 on each assignment and we have to show work and shit...

along with quizzes/tests we can never use notes not even equations...we have to like know it like wtf i cant do that..

 

Standard form is ax^2+bx+c=0 yes?
If so I don't get how it's giving you a hard time....
First: -x^2 - 15 = 0
Second: -x^2+2x-1=0

Quadratic formula is the easiest way.
cba doing it out for you but it is (-b+or-sqrt(b^2-4ac))/2a

 

If you have a graphing calculator you can plug it into that using the y function tool, then press second graph and find the corresponding number to the number after the = sign.

 

And uhh... I don't think A in standard form can be negative? Correct?

 

Sure it can.

 

Are you sure? I've always learned in the ax + by + c = 0 formula, A has to be positive.

 

i get the a,b,c part but dont get how to do it after lol

 

A is always depicted as positive in standard form, but it can be negative.

Have you ever used a diamond problem?