SOLUTION: please help me solve and graph this equation: 5x^2-20x-60=0

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Question 199679: please help me solve and graph this equation: 5x^2-20x-60=0
Found 2 solutions by Alan3354, jim_thompson5910:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
5x^2-20x-60=0
x^2 - 4x - 12 = 0
(x-8)*(x+4) = 0
x = 8, x = -4
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To graph it, get the FREE software at
www.padowan.dk.com/graph/

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

5x%5E2-20x-60=0 Start with the given equation.


Notice we have a quadratic in the form of Ax%5E2%2BBx%2BC where A=5, B=-20, and C=-60


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-%28-20%29+%2B-+sqrt%28+%28-20%29%5E2-4%285%29%28-60%29+%29%29%2F%282%285%29%29 Plug in A=5, B=-20, and C=-60


x+=+%2820+%2B-+sqrt%28+%28-20%29%5E2-4%285%29%28-60%29+%29%29%2F%282%285%29%29 Negate -20 to get 20.


x+=+%2820+%2B-+sqrt%28+400-4%285%29%28-60%29+%29%29%2F%282%285%29%29 Square -20 to get 400.


x+=+%2820+%2B-+sqrt%28+400--1200+%29%29%2F%282%285%29%29 Multiply 4%285%29%28-60%29 to get -1200


x+=+%2820+%2B-+sqrt%28+400%2B1200+%29%29%2F%282%285%29%29 Rewrite sqrt%28400--1200%29 as sqrt%28400%2B1200%29


x+=+%2820+%2B-+sqrt%28+1600+%29%29%2F%282%285%29%29 Add 400 to 1200 to get 1600


x+=+%2820+%2B-+sqrt%28+1600+%29%29%2F%2810%29 Multiply 2 and 5 to get 10.


x+=+%2820+%2B-+40%29%2F%2810%29 Take the square root of 1600 to get 40.


x+=+%2820+%2B+40%29%2F%2810%29 or x+=+%2820+-+40%29%2F%2810%29 Break up the expression.


x+=+%2860%29%2F%2810%29 or x+=++%28-20%29%2F%2810%29 Combine like terms.


x+=+6 or x+=+-2 Simplify.


So the solutions are x+=+6 or x+=+-2