solve for Y. 5y^2 - 11y +2 = 0?

2008-05-23 4:42 pm
solve for Y.

5y^2 - 11y +2 = 0

回答 (7)

2008-05-23 4:45 pm
✔ 最佳答案
5y^2 - 11y + 2 = 0
(5y - 1)(y - 2) = 0
y = 1/5 or 2

*βω*
2008-05-23 5:02 pm
y = ~0.1429
______________________

5y^2-11y+2 = 0
-2 -2

5y*5y-11y = -2
25y-11y = -2
14y = -2
----- -----
14 14

y=1429



It's probably wrong because i suck at math, but it was fun working out... and it did equal 0... albiet 0.95, it's a zero whole number i guess... i don't know...
2008-05-23 5:02 pm
5y^2 - 11y + 2 = 0
(5y - 1)(5y - 2) = 0

5y - 1 - 0
5y = 1
y = 1/5 (0.2)

5y - 2 = 0
5y = 2
y = 2/5 (0.4)

∴ y = 1/5 (0.2) , 2/5 (0.4)
2008-05-23 4:54 pm
Factor it!
Note the coefficient 5, in the 5y^2 term, and the constant 2.

The 5 gives you something like:
(5y - ____)(y - ____)

The fact that the 2 is positive means either that you will have two postive or two negative constant terms, like this:
(____ + 1)(____ + 2) or (____ - 1)(____ - 2)
Since the middle term of your equation is -11y, we must use the two negatives.

So the pieces of our puzzle are:
(5y - ____)(y - ____) and (____ - 1)(____ - 2)

Putting it all together, we get either:
(5y - 1)(y - 2) or (5y - 2)(y - 1)

Now you have to decide which one it is--I won't finish it for you!
2008-05-23 4:50 pm
ax^2 + bx +c = 0

first find the discriminant:

d = b^2 - 4*a*c
d = (-11)^2 - 4*5*2 = 121-40 = 81

the 2 solutions is then:

x = (-b +/- sqrt(d)) /(2*a)

x = (11 +/- 9) /(10)
x = 2 and x = 2/10 = 1/5 = 0.2
2008-05-23 4:50 pm
5y^2 - 11y +2 = 0
5y^2-10y-y+2=0
5y(y-2)-1(y-2)=0
(y-2)(5y-1)=0
y-2=0 means y=2
5y-1=0 means 5y=1 or y=1/5
2008-05-23 4:47 pm
5y^2 - 11y + 2 = 5y^2 - 10y - y + 2 = 5y(y-2) - (y-2) = (5y-1)(y-2) = 0 when y=2 or y=1/5.


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