SOLUTION: We are stumped Problem, solve equation: 18y^2+24y+18=0 we tried this 18y^2+12y+12y+8=0 6y(3y+2) 4(3y+2)=0 (6y+4)(3y+2)=0 2(3y+2)(3y+2)=0 2(9y^2+4)=0 18y^2+8=0 -8=-8(from

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: We are stumped Problem, solve equation: 18y^2+24y+18=0 we tried this 18y^2+12y+12y+8=0 6y(3y+2) 4(3y+2)=0 (6y+4)(3y+2)=0 2(3y+2)(3y+2)=0 2(9y^2+4)=0 18y^2+8=0 -8=-8(from       Log On


   

Question 422669: We are stumped
Problem, solve equation:
18y^2+24y+18=0
we tried this
18y^2+12y+12y+8=0
6y(3y+2) 4(3y+2)=0
(6y+4)(3y+2)=0
2(3y+2)(3y+2)=0
2(9y^2+4)=0
18y^2+8=0
-8=-8(from both sides)
18y^2=-8 we got this far
but the answer is -2/3, where did we go wrong??? Help!
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
You made a mistake in thinking that %283y%2B2%29%283y%2B2%29 multiplies out to 9y%5E2%2B4; however, it really multiplies out to 9y%5E2%2B12y%2B4


18y%5E2%2B24y%2B8=0 Start with the given equation.


Notice that the quadratic 18y%5E2%2B24y%2B8 is in the form of Ay%5E2%2BBy%2BC where A=18, B=24, and C=8


Let's use the quadratic formula to solve for "y":


y+=+%28-B+%2B-+sqrt%28+B%5E2-4AC+%29%29%2F%282A%29 Start with the quadratic formula


y+=+%28-%2824%29+%2B-+sqrt%28+%2824%29%5E2-4%2818%29%288%29+%29%29%2F%282%2818%29%29 Plug in A=18, B=24, and C=8


y+=+%28-24+%2B-+sqrt%28+576-4%2818%29%288%29+%29%29%2F%282%2818%29%29 Square 24 to get 576.


y+=+%28-24+%2B-+sqrt%28+576-576+%29%29%2F%282%2818%29%29 Multiply 4%2818%29%288%29 to get 576


y+=+%28-24+%2B-+sqrt%28+0+%29%29%2F%282%2818%29%29 Subtract 576 from 576 to get 0


y+=+%28-24+%2B-+sqrt%28+0+%29%29%2F%2836%29 Multiply 2 and 18 to get 36.


y+=+%28-24+%2B-+0%29%2F%2836%29 Take the square root of 0 to get 0.


y+=+%28-24+%2B+0%29%2F%2836%29 or y+=+%28-24+-+0%29%2F%2836%29 Break up the expression.


y+=+%28-24%29%2F%2836%29 or y+=++%28-24%29%2F%2836%29 Combine like terms.


y+=+-2%2F3 or y+=+-2%2F3 Simplify.


So the solution is y+=+-2%2F3


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