SOLUTION: I really need help with this 4 part equation.I have looked at it and just stumped could someone please help me. A.Without solving the equation or factoring , determine the solutio

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: I really need help with this 4 part equation.I have looked at it and just stumped could someone please help me. A.Without solving the equation or factoring , determine the solutio      Log On


   

Question 150601This question is from textbook
: I really need help with this 4 part equation.I have looked at it and just stumped could someone please help me.
A.Without solving the equation or factoring , determine the solutions to the equation x^2-2x-8=0 by inspecting the graph. why?
B. Does the function have a maximum or a minimum?
C. What is the eqution of the line of symmetry for this graph?
D. What are the coordinates of the vertex in (x,y)form? This question is from textbook

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+graph%28+700%2C+700%2C+-8%2C+10%2C+-10%2C+5%2C+x%5E2+-+2x+-+8%29+
The crossings of the x-axis, x+=+4, and x+=+-2
are the solutions, because those values both make
x%5E2+-+2x+-+8+=+0 true
Rewriting, x+-+4+=+0 and x+%2B+2+=+0 give me
the factors of the equation, since
%28x+-+4%29%28x+%2B+2%29+=+x%5E2+-+2x+-+8
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The function has a minimum which is exactly midway between
the roots. To find the x-coordinate of the midpoint,
%284+%2B+%28-2%29%29%2F2+=+1
Another way to find the x-coordinate of the vertex is
to use the formula %28-b%29%2F%282a%29, where
ax%5E2+%2B+bx+%2B+c+=+0 is the general formula
In this case, a+=+1, b+=+-2
%28-b%29%2F%282a%29+=+-%28-2%29%2F%282%2A1%29+=+1