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Solve the equations x = 8y + 1 and x^2 = 2y - 2

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xetabeta | Student, Kindergarten | Salutatorian

Posted October 9, 2012 at 9:41 AM via web

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Solve the equations x = 8y + 1 and x^2 = 2y - 2

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jeew-m | College Teacher | (Level 1) Educator Emeritus

Posted October 9, 2012 at 10:11 AM (Answer #1)

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`x = 8y+1`

`x^2 = (8y+1)^2`

 

But;

`x^2 = 2y-2`

 

`(8y+1)^2 = 2y-2`

`64y^2+16y+1 = 2y-2`

`64y^2+14y+3 = 0`


The solution of the above equation is;

`y = (-14+-sqrt(14^2-4*64*3))/(2*64)`

 

`y = -7/64`

 

Therefore

`x = 8y+1 = 8*(-7/64)+1 = 1/8`

 

So the answers are;

`x = 1/8`

`y = -7/64`

 

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