SOLUTION: Please help me solve this equation: {{{ x^2-2x-3=0 }}}.

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Question 207718: Please help me solve this equation: +x%5E2-2x-3=0+.
Found 2 solutions by jim_thompson5910, stanbon:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2-2x-3=0 Start with the given equation.


Notice that the quadratic x%5E2-2x-3 is in the form of Ax%5E2%2BBx%2BC where A=1, B=-2, and C=-3


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-%28-2%29+%2B-+sqrt%28+%28-2%29%5E2-4%281%29%28-3%29+%29%29%2F%282%281%29%29 Plug in A=1, B=-2, and C=-3


x+=+%282+%2B-+sqrt%28+%28-2%29%5E2-4%281%29%28-3%29+%29%29%2F%282%281%29%29 Negate -2 to get 2.


x+=+%282+%2B-+sqrt%28+4-4%281%29%28-3%29+%29%29%2F%282%281%29%29 Square -2 to get 4.


x+=+%282+%2B-+sqrt%28+4--12+%29%29%2F%282%281%29%29 Multiply 4%281%29%28-3%29 to get -12


x+=+%282+%2B-+sqrt%28+4%2B12+%29%29%2F%282%281%29%29 Rewrite sqrt%284--12%29 as sqrt%284%2B12%29


x+=+%282+%2B-+sqrt%28+16+%29%29%2F%282%281%29%29 Add 4 to 12 to get 16


x+=+%282+%2B-+sqrt%28+16+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


x+=+%282+%2B-+4%29%2F%282%29 Take the square root of 16 to get 4.


x+=+%282+%2B+4%29%2F%282%29 or x+=+%282+-+4%29%2F%282%29 Break up the expression.


x+=+%286%29%2F%282%29 or x+=++%28-2%29%2F%282%29 Combine like terms.


x+=+3 or x+=+-1 Simplify.


So the solutions are x+=+3 or x+=+-1


Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
x^2-2x-3=0
(x-3)(x+1) = 0
x = 3 or x = -1
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Cheers,
Stan H.