SOLUTION: how do you solve -x^2-6x+9=0

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Question 201945This question is from textbook algebra 1
: how do you solve -x^2-6x+9=0 This question is from textbook algebra 1

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
I'm assuming that it's supposed to be -x%5E2-6x%2B9=0




-x%5E2-6x%2B9=0 Start with the given equation.


Notice that the quadratic -x%5E2-6x%2B9 is in the form of Ax%5E2%2BBx%2BC where A=-1, B=-6, and C=9


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-%28-6%29+%2B-+sqrt%28+%28-6%29%5E2-4%28-1%29%289%29+%29%29%2F%282%28-1%29%29 Plug in A=-1, B=-6, and C=9


x+=+%286+%2B-+sqrt%28+%28-6%29%5E2-4%28-1%29%289%29+%29%29%2F%282%28-1%29%29 Negate -6 to get 6.


x+=+%286+%2B-+sqrt%28+36-4%28-1%29%289%29+%29%29%2F%282%28-1%29%29 Square -6 to get 36.


x+=+%286+%2B-+sqrt%28+36--36+%29%29%2F%282%28-1%29%29 Multiply 4%28-1%29%289%29 to get -36


x+=+%286+%2B-+sqrt%28+36%2B36+%29%29%2F%282%28-1%29%29 Rewrite sqrt%2836--36%29 as sqrt%2836%2B36%29


x+=+%286+%2B-+sqrt%28+72+%29%29%2F%282%28-1%29%29 Add 36 to 36 to get 72


x+=+%286+%2B-+sqrt%28+72+%29%29%2F%28-2%29 Multiply 2 and -1 to get -2.


x+=+%286+%2B-+6%2Asqrt%282%29%29%2F%28-2%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


x+=+%286%29%2F%28-2%29+%2B-+%286%2Asqrt%282%29%29%2F%28-2%29 Break up the fraction.


x+=+-3+%2B-+-3%2Asqrt%282%29 Reduce.


x+=+-3-3%2Asqrt%282%29 or x+=+-3%2B3%2Asqrt%282%29 Break up the expression.


So the solutions are x+=+-3-3%2Asqrt%282%29 or x+=+-3%2B3%2Asqrt%282%29


which approximate to x=-7.243 or x=1.243