SOLUTION: Find the constant of integration, C if y=∫(9x^2+2x-9 )dx and the curve passes through the point (3,8)

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Question 827228: Find the constant of integration, C if y=∫(9x^2+2x-9 )dx and the curve passes through the point (3,8)
Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!

  y=int%28%289x%5E2%2B2x-9%29%2Cdx%29%22%22=%22%22int%28%289x%5E2%29%2Cdx%29%2Bint%28%282x%29%2Cdx%29%2Bint%28%28-9%29%2Cdx%29%22%22=%22%229int%28%28x%5E2%29%2Cdx%29%2B2int%28%28x%29%2Cdx%29-9int%28dx%29%22%22=%22%22
9%28x%5E3%2F3%29%2B2%28x%5E2%2F2%29-9x%2BC%22%22=%22%223x%5E3%2Bx%5E2-9x%2BC

  y = 3x³+x²-9x+C

Substitute (x,y) = (3,8)

  8 = 3(3)³+(3)²-9(3)+C
  8 = 3(27)+9-27+C
  8 = 81+9-27+C
  8 = 63+C
-55 = C

Edwin