SOLUTION: Solve by using the quadratic formula. x^2 = –x + 4

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Question 104966: Solve by using the quadratic formula. x^2 = –x + 4
Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
Start with the given equation


Subtract from both sides

Solved by pluggable solver: Quadratic Formula
Let's use the quadratic formula to solve for x:


Starting with the general quadratic





the general solution using the quadratic equation is:







So lets solve ( notice , , and )





Plug in a=-1, b=-1, and c=4




Negate -1 to get 1




Square -1 to get 1 (note: remember when you square -1, you must square the negative as well. This is because .)




Multiply to get




Combine like terms in the radicand (everything under the square root)




Simplify the square root (note: If you need help with simplifying the square root, check out this solver)




Multiply 2 and -1 to get -2


So now the expression breaks down into two parts


or



Now break up the fraction



or



Simplify



or



So the solutions are:

or




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