SOLUTION: Y=x2+2x-3 Y=5

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Question 727187: Y=x2+2x-3
Y=5
Answer by MathLover1(20850) About Me  (Show Source):
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y=x%5E2%2B2x-3...eq. 1...parabola
y=5...eq. 2.......horizontal line
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y=x%5E2%2B2x-3..substitute y from eq. 2
5=x%5E2%2B2x-3....solve for x
0=x%5E2%2B2x-3-5
x%5E2%2B2x-8=0..use quadratic formula
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%28-2+%2B-+sqrt%28+2%5E2-4%2A1%2A%28-8%29+%29%29%2F%282%2A1%29+
x+=+%28-2+%2B-+sqrt%28+4%2B32+%29%29%2F2+
x+=+%28-2+%2B-+sqrt%2836+%29%29%2F2+
x+=+%28-2+%2B-+6%29%2F2+
solutions:
x+=+%28-2+%2B+6%29%2F2+
x+=+4%2F2+
x+=+2+
or
x+=+%28-2-+6%29%2F2+
x+=+-8%2F2+
x+=+-4
so, parabola and horizontal line intersecting in two points and they are:(2,5) and (-4,5)