SOLUTION: Solve using the quadratic formula: x^2 – 7x – 1 = -7

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Question 147239: Solve using the quadratic formula:
x^2 – 7x – 1 = -7
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2-7x-1=-7 Start with the given equation.


x%5E2-7x-1%2B7=0 Get all terms to the left side.


x%5E2-7x%2B6=0 Combine like terms.


Notice we have a quadratic equation in the form of ax%5E2%2Bbx%2Bc where a=1, b=-7, and c=6


Let's use the quadratic formula to solve for x


x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29 Start with the quadratic formula


x+=+%28-%28-7%29+%2B-+sqrt%28+%28-7%29%5E2-4%281%29%286%29+%29%29%2F%282%281%29%29 Plug in a=1, b=-7, and c=6


x+=+%287+%2B-+sqrt%28+%28-7%29%5E2-4%281%29%286%29+%29%29%2F%282%281%29%29 Negate -7 to get 7.


x+=+%287+%2B-+sqrt%28+49-4%281%29%286%29+%29%29%2F%282%281%29%29 Square -7 to get 49.


x+=+%287+%2B-+sqrt%28+49-24+%29%29%2F%282%281%29%29 Multiply 4%281%29%286%29 to get 24


x+=+%287+%2B-+sqrt%28+25+%29%29%2F%282%281%29%29 Subtract 24 from 49 to get 25


x+=+%287+%2B-+sqrt%28+25+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


x+=+%287+%2B-+5%29%2F%282%29 Take the square root of 25 to get 5.


x+=+%287+%2B+5%29%2F%282%29 or x+=+%287+-+5%29%2F%282%29 Break up the expression.


x+=+%2812%29%2F%282%29 or x+=++%282%29%2F%282%29 Combine like terms.


x+=+6 or x+=+1 Simplify.


So our answers are x+=+6 or x+=+1