Use factoring to solve the equation.
5 y^2 - 20 = 0
2007-05-13 09:16:51 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Well, since Answerer #1 isn't planning on helping I'll show you how it works.
5y^2 - 20 = 0
Add 20 to both sides.
5y^2 = 20
Divide both sides by 5 (factoring a 5)
y^2 = 4
Take the square root of 4
y = +/- 2
BTW, there are other answerers below who show factoring and are also correct.
2007-05-13 09:19:49 · answer #1 · answered by Carl D 4 · 1⤊ 0⤋
What Carl said.
Me, I don't practice, I either can't figure out a homework problem and ask here...or show the answer I came up with when in doubt. Come on...be honest with yourself.
You can try it this way...actually show the factoring 5y^2-20=0
therefore 5 (y^2-4)
that factors further to
5(y+2)(y-2)
so y is equal to +2 and -2.
2007-05-13 09:23:36 · answer #2 · answered by Mike C 6 · 0⤊ 0⤋
I believe you wanted to see how to solve using factoring:
5y^2 - 20 = 0
5(y^2 - 4) = 0
5(y + 2)(y - 2) = 0
y = -2,2
...which, incidentally, is a good way of showing why y^2 = 4 has both positive and negative roots.
2007-05-13 09:32:10 · answer #3 · answered by Helmut 7 · 0⤊ 0⤋
its kinda banal: y=2 or y=-2
in fact
5*2^2-20=5*4-20=20-20=0
5*(-2)^2-20=5*4-20=20-20=0
you can also find it out this way
5y^2-20=0
5y^2=20
y^2=20/5=4
y=sqrt(4)
which is 2 and -2
byeee
hope i helped
2007-05-13 09:22:01 · answer #4 · answered by vale l 3 · 0⤊ 0⤋
Well where is your practice answer then?
If she had given her practice answer and there was a mistake I would have been happy to help.
Sometimes doing something for some-one isn't as helpful as it might appear.
2007-05-13 09:19:45 · answer #5 · answered by Anonymous · 0⤊ 1⤋