SOLUTION: at what points does the graph of y=2x^2-4x-16 intersect the x-axis?

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Question 184401: at what points does the graph of y=2x^2-4x-16 intersect the x-axis?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The graph crosses the x-axis wherever y=0
Set y+=+o
2x%5E2+-+4x+-+16+=+0
Use quadratic formula with ax%5E2+%2B+bx+%2B+c+=+0
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
a+=+2
b+=+-4
c+=+-16
x+=+%28-%28-4%29+%2B-+sqrt%28+%28-4%29%5E2-4%2A2%2A%28-16%29+%29%29%2F%282%2A2%29+
x+=+%284+%2B-+sqrt%28+16+%2B+128+%29%29%2F4+
x+=+%284+%2B-+sqrt%28+144+%29%29%2F4+
x+=+%284+%2B-+12%29%2F4+
x+=+%284+%2B+12%29%2F4
x+=+4
and
x+=+4+-+12%29%2F4
x+=+-2
the graph crosses the x-axis at x+=+-2 and x+=+4
Here's a plot:
+graph%28+500%2C+500%2C+-4%2C+7%2C+-18%2C+4%2C+2x%5E2+-+4x+-+16%29+