SOLUTION: x^2 +10x-4=0

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Question 378722: x^2 +10x-4=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2%2B10x-4=0 Start with the given equation.


Notice that the quadratic x%5E2%2B10x-4 is in the form of Ax%5E2%2BBx%2BC where A=1, B=10, and C=-4


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-%2810%29+%2B-+sqrt%28+%2810%29%5E2-4%281%29%28-4%29+%29%29%2F%282%281%29%29 Plug in A=1, B=10, and C=-4


x+=+%28-10+%2B-+sqrt%28+100-4%281%29%28-4%29+%29%29%2F%282%281%29%29 Square 10 to get 100.


x+=+%28-10+%2B-+sqrt%28+100--16+%29%29%2F%282%281%29%29 Multiply 4%281%29%28-4%29 to get -16


x+=+%28-10+%2B-+sqrt%28+100%2B16+%29%29%2F%282%281%29%29 Rewrite sqrt%28100--16%29 as sqrt%28100%2B16%29


x+=+%28-10+%2B-+sqrt%28+116+%29%29%2F%282%281%29%29 Add 100 to 16 to get 116


x+=+%28-10+%2B-+sqrt%28+116+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


x+=+%28-10+%2B-+2%2Asqrt%2829%29%29%2F%282%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


x+=+%28-10%29%2F%282%29+%2B-+%282%2Asqrt%2829%29%29%2F%282%29 Break up the fraction.


x+=+-5+%2B-+sqrt%2829%29 Reduce.


x+=+-5%2Bsqrt%2829%29 or x+=+-5-sqrt%2829%29 Break up the expression.


So the solutions are x+=+-5%2Bsqrt%2829%29 or x+=+-5-sqrt%2829%29


If you need more help, email me at jim_thompson5910@hotmail.com

Also, feel free to check out my tutoring website

Jim