SOLUTION: Use substitution with the two equations and determine the points of intersection. y=x^2-1 y=x

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Question 228281: Use substitution with the two equations and determine the points of intersection.
y=x^2-1
y=x
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
y=x^2-1
y=x
REPLACING Y WITH X IN THE FIRST EQUATION WE GET:
X=X^2-1
X^2-X-1=0
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
X=(1+-SQRT[-1^2-4*1*-1])/2*1
X=(1+-SQRT1+4)/2
X=(1+-SQRT5)/2
X=(1+-2.236) /2
X=(1+2.236)/2
X=3.236/2
X=1.618 ANS. Y=1.618 ANS.
X=(1-2.236)/2
X=-1.236/2
X=-.618 ANS. Y=-.618 ANS
PROOF:
1.618=1.618^2-1
1.618=2.618-1
1.618=1.618
-.618=-.618^2-1
-.618=.382-1
-.618=-.618