a. 5x^2+10x=9+5y^2
b. 5x^2-10x=0-5y^2
c. 5x^2+5x+y^2=9
d. 5x^2+10x+5y=9
2007-01-31 03:49:21 · 6 answers · asked by Anna 1 in Science & Mathematics ➔ Mathematics
a circle is x^2+y^2=r^2
thusly, d is a circle.
2007-01-31 03:55:23 · answer #1 · answered by Tamino 2 · 0⤊ 2⤋
The answer is b:
The general form of a circle equotation is (x-x0)^2+(y-y0)^2=r^2 where (x0,y0) is the center of the circle and the r it's radius. So we will make it in this form. We have:
5x^2-10x=-5y^2 <=>
5x^2+5y^2-10x=0 <=> (divided by 5)
x^2+y^2-2x=0.
(We have (x-x0)^2=x^2-2*x*x0+x0^2 so we will try to form it. Here 2*x = 2*x*x0 so x0=1)
x^2+y^2-2x=0 <=> (add 1^2)
x^2-2x+1^2+y^2=1^2 <=>
(x-1)^2+(y-0)^21^2.
So it is a circle with center C(1,0) and radius 1.
2007-01-31 12:14:53 · answer #2 · answered by costasgr43 2 · 1⤊ 0⤋
The answer is b.
Why? Let's divide out 5:
x² - 2x + y² = 0
Complete the square in x:
x² - 2x + 1 + y² = 1
or
(x-1)² + y² = 1.
This is the equation of a circle with centre (1,0) and
radius 1.
2007-01-31 12:14:48 · answer #3 · answered by steiner1745 7 · 1⤊ 0⤋
I already answered you that this is not a circle and what the equation of a circumference is.
You arent doing any effort, you have posted lots of questions, some of them were quite easy.
Ana
2007-01-31 11:59:16 · answer #4 · answered by MathTutor 6 · 0⤊ 3⤋
b
2007-01-31 12:02:19 · answer #5 · answered by mrmcdoughnut 2 · 0⤊ 0⤋
the answer is b)
2007-01-31 11:57:44 · answer #6 · answered by santmann2002 7 · 2⤊ 0⤋