Question

Does anybody know how I can use these two equations x^2 =-y and x=-y^2 to find the points (0,0) and (-1,-1)?
these are what I have done
I plug equation1 into equation2-->x=(x^2)^2-->x=x^4-->0=x^4 -x--> 0=x(x^3 -1)-->x=0 and1
Now I plug those points into equation1--> (0)^2 =-y-->0=y so point1= (0,0), (1)^2 =-y-->y=-1 so point2=(1,-1) What did I do wrong?

Answer 1

well, (0,0) is clearly a solution
x = -y^2, so
x^2 = (-y^2)^2 = y^4 = -y
y^3 = -1
y = -1
So, x = -(-1)^2 = -(-1) = 1
so (1,-1) also a solution

Answer 2

check that 2nd last line:
So, x = -(-1)^2 = -(-1) = 1
so (1,-1) also a solution

should be:
So, x = -(-1)^2 = -(+1) = -1
so (-1,-1) also a solution

@ anonymous
Why are you repeating this question when it was answered yesterday,
and you even acknowledged that you got it.
This just makes tutors doing unnecessary work.

https://www.jiskha.com/questions/1828146/can-somebody-explains-what-i-did-wrong-find-the-points-0-0-and-1-1-eq1-x-2-y

Btw, give yourself a nickname, it makes things so much easier.

Answer 3

I have a lot to do so when I go from one subject to another, I forgot what I have done the day before sometime even hours before. Poor memory or too much stress. I told my teacher that I can not learn just by doing homework. I need time to review or I learn nothing but his way of learning is by doing lot of homework and assignment, which is worst for me.

Answer 4

If you'd give yourself a nickname, as Reiny suggested, that would help. Then you could use Ctrl+F to <u>find</u> your previous posts.

In addition, if you bookmark each question you post (Ctrl+D on a PC), you'll easily be able to find what you've already posted and check back to find the tutors' replies.