SOLUTION: Solve for x:2 to the power of x^2 -5x = 8 Please show steps Thank you:) Hey thanks for trying I truly do appreciate it however the answer is x = 5 plus/minus √37

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: Solve for x:2 to the power of x^2 -5x = 8 Please show steps Thank you:) Hey thanks for trying I truly do appreciate it however the answer is x = 5 plus/minus √37      Log On


   



Question 133330: Solve for x:2 to the power of x^2 -5x = 8
Please show steps
Thank you:)

Hey thanks for trying I truly do appreciate it however the answer is
x = 5 plus/minus √37 /(2)
Can someone correct this?

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
2%5E%28x%5E2+-5x%29+=+8 Start with the given equation


2%5E%28x%5E2+-5x%29+=+2%5E3 Rewrite 8 as 2%5E3


Since the bases are equal, this means that the exponents are equal


So x%5E2+-5x=3


x%5E2+-5x=3 Set the exponents equal to one another


x%5E2-5x-3=0 Subtract 3 from both sides.


Let's use the quadratic formula to solve for x:


Starting with the general quadratic

ax%5E2%2Bbx%2Bc=0

the general solution using the quadratic equation is:

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29



So lets solve x%5E2-5%2Ax-3=0 ( notice a=1, b=-5, and c=-3)




x+=+%28--5+%2B-+sqrt%28+%28-5%29%5E2-4%2A1%2A-3+%29%29%2F%282%2A1%29 Plug in a=1, b=-5, and c=-3



x+=+%285+%2B-+sqrt%28+%28-5%29%5E2-4%2A1%2A-3+%29%29%2F%282%2A1%29 Negate -5 to get 5



x+=+%285+%2B-+sqrt%28+25-4%2A1%2A-3+%29%29%2F%282%2A1%29 Square -5 to get 25 (note: remember when you square -5, you must square the negative as well. This is because %28-5%29%5E2=-5%2A-5=25.)



x+=+%285+%2B-+sqrt%28+25%2B12+%29%29%2F%282%2A1%29 Multiply -4%2A-3%2A1 to get 12



x+=+%285+%2B-+sqrt%28+37+%29%29%2F%282%2A1%29 Combine like terms in the radicand (everything under the square root)



x+=+%285+%2B-+sqrt%2837%29%29%2F2 Multiply 2 and 1 to get 2


So now the expression breaks down into two parts

x+=+%285+%2B+sqrt%2837%29%29%2F2 or x+=+%285+-+sqrt%2837%29%29%2F2




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Answer:

So the solutions are

x+=+%285+%2B+sqrt%2837%29%29%2F2 or x+=+%285+-+sqrt%2837%29%29%2F2