SOLUTION: X2-3x-10=0

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Question 183291: X2-3x-10=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2-3x-10=0 Start with the given equation.


Notice we have a quadratic equation in the form of ax%5E2%2Bbx%2Bc where a=1, b=-3, and c=-10


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-%28-3%29+%2B-+sqrt%28+%28-3%29%5E2-4%281%29%28-10%29+%29%29%2F%282%281%29%29 Plug in a=1, b=-3, and c=-10


x+=+%283+%2B-+sqrt%28+%28-3%29%5E2-4%281%29%28-10%29+%29%29%2F%282%281%29%29 Negate -3 to get 3.


x+=+%283+%2B-+sqrt%28+9-4%281%29%28-10%29+%29%29%2F%282%281%29%29 Square -3 to get 9.


x+=+%283+%2B-+sqrt%28+9--40+%29%29%2F%282%281%29%29 Multiply 4%281%29%28-10%29 to get -40


x+=+%283+%2B-+sqrt%28+9%2B40+%29%29%2F%282%281%29%29 Rewrite sqrt%289--40%29 as sqrt%289%2B40%29


x+=+%283+%2B-+sqrt%28+49+%29%29%2F%282%281%29%29 Add 9 to 40 to get 49


x+=+%283+%2B-+sqrt%28+49+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


x+=+%283+%2B-+7%29%2F%282%29 Take the square root of 49 to get 7.


x+=+%283+%2B+7%29%2F%282%29 or x+=+%283+-+7%29%2F%282%29 Break up the expression.


x+=+%2810%29%2F%282%29 or x+=++%28-4%29%2F%282%29 Combine like terms.


x+=+5 or x+=+-2 Simplify.


So the answers are x+=+5 or x+=+-2