Solve the system:
x^2 + y^2 = 4
x^2 - y^2 = 4
i dont understand...
these are the choices
1. (2,0), (2,2)
2. (2,0), (-2,0)
3. (-2,0), (-2,2)
4. (2,2), (-2,2)
and from my math work, i got number 2 as the answer...
please helP!
2007-04-30 16:33:22 · 10 answers · asked by ali_ed2001 2 in Science & Mathematics ➔ Mathematics
add them together and you get:
2x^2 = 8
x^2 = 4
x = +/-2
Put the x back in
2^2 + y^2 = 4
4 + y^2 =4
y^2 = 0
y = 0
so the correct answer is 2
2007-04-30 16:38:10 · answer #1 · answered by jules0512 2 · 1⤊ 0⤋
The first equation is a circle, the second is a hyperbola.
Since you have the answer choices, the simplest way to figure out which is a solution set.. is to substitute the values into the equations. The set that works in both equations is the correct solution set.
x^2 + y^2 = 4
x^2 - y^2 = 4
(2,0), (-2,0)
(2)^2 + (0)^2 = 4 is true
(-2)^2 - (0)^2 = 4 is also true
Therefore, (2,0) and (-2,0) are solutions.
2007-04-30 23:40:50 · answer #2 · answered by suesysgoddess 6 · 1⤊ 0⤋
Plug them in to see what works. Try #2.
(x,y), (x,y)
(2,0), (-2,0)
2^2 + 0^2 = 4 + 0 = 4
-2^2 + 0^2 = 4 + 0 = 4
2007-04-30 23:41:28 · answer #3 · answered by spmdrumbass 4 · 0⤊ 0⤋
answer is the second option let x^2 be a
and y^2 be b
therfore a+b=4
a-b=4
solving these we have
a=4 and b =0
that means x^2 = 4
x= +2 or - 2
y=+0 or -0 or simply 0,0
thaer fore 2,0 and -2,0 is the answer
2007-04-30 23:41:46 · answer #4 · answered by Anonymous · 0⤊ 0⤋
2. (2, 0), (-2,0)
think, if y is zero in both cases, then x^2 minus or plus y^2 would be the same. 2 squared and -2 squared are both 4.
2007-04-30 23:39:01 · answer #5 · answered by cool girl 5 · 0⤊ 0⤋
2x² = 8
x² = 4
x = ± 2
When x = 2, y = 0
When x = - 2, y = 0
Solns. are (2,0) and (-2,0)
This is ANSWER 2.
(which agrees with your answer---thank goodness!)
2007-05-01 05:03:37 · answer #6 · answered by Como 7 · 0⤊ 0⤋
add 2 formula together.
you will figure it out.
it is quadratic equation, there can be 2 values of X.
Then, there will be 2 values of Y.
(2,0) means value of x is 2 and value of y is 0
good luck
2007-04-30 23:39:32 · answer #7 · answered by modern wushu 2 · 0⤊ 0⤋
number two is the correct answer. for each pair of numbers, you can plug the first value in for x, and the second value in for y. if you plug in x=2, y=0 both equations are true. if you plug in x= -2, y=0, both equations are true. this means that the correct answer is 2.
2007-04-30 23:39:01 · answer #8 · answered by horrid 3 · 0⤊ 0⤋
This is a circle equation! graph them.
rgds
2007-04-30 23:37:24 · answer #9 · answered by andtovar 2 · 0⤊ 1⤋
good job!!!!!!!!! you did it correctly
2007-04-30 23:41:18 · answer #10 · answered by :) 5 · 0⤊ 0⤋