SOLUTION: what are the x intercepts of -x^2+4x+1

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Question 651774: what are the x intercepts of -x^2+4x+1
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
you have the quadratic in the form ax%5E2%2Bb%2Bc
set it equal to zero and solve for x
-x%5E2%2B4x%2B1=0...use quadratic formula
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ...note that a=-1, b=4 and c=1
x+=+%28-4+%2B-+sqrt%28+4%5E2-4%2A%28-1%29%2A1+%29%29%2F%282%2A%28-1%29%29+

x+=+%28-4+%2B-+sqrt%28+16%2B4+%29%29%2F%28-2%29+
x+=+%28-4+%2B-+sqrt%28+20%29%29%2F%28-2%29+
x+=+%28-4+%2B-++4.47+%29%2F%28-2%29+
solutions:
x+=+%28-4+%2B4.47+%29%2F%28-2%29+
x+=+0.47+%2F-2+
x+=+-0.235+..........first x-intercept is at point (-0.235+,0)
or
x+=+%28-4+-4.47+%29%2F%28-2%29+
x+=+-8.47+%2F-2+
x+=4.235+..............second x-intercept is at point (4.235+,0)



+graph%28+600%2C+600%2C+-6%2C+6%2C+-6%2C+6%2C+-x%5E2%2B4x%2B1%29+