SOLUTION: give exact and approximate solutions to three decimal places: y^2-8y+16=1

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Question 259986: give exact and approximate solutions to three decimal places: y^2-8y+16=1
Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
give exact and approximate solutions to three decimal places: y^2-8y+16=1

y%5E2-8y%2B16=1

Subtract 1 from both sides to get 0 on the right side:

y%5E2-8y%2B15=0

You can factor that as

%28y-3%29%28y-5%29=0

Set each equal to 0:

y-3=0
y=3

y-5=0
y=5

But since you mentioned decimal approximating that
made me think you were supposed to do it using
the quadratic formula:

You would use y for x, 1 for a,

-8 for b and 15 for c

y%5E2-8y%2B15=0

 x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ 

 

  x+=+%28-%28-8%29+%2B-+sqrt%2864-60+%29%29%2F2+

  x+=+%288+%2B-+sqrt%284%29%29%2F2+

  x = (8±2)/2 

Using the +,

  x+=+%288+%2B+2%29%2F2+
  x+=+10%2F2+  
  x=5

Using the -,

  x+=+%288+-+2%29%2F2+
  x+=+6%2F2+  
  x=3

Edwin