Andrew M. answered • 08/29/17
Tutor
New to Wyzant
Mathematics - Algebra a Specialty / F.I.T. Grad - B.S. w/Honors
y = √(x+5)
It is a function if it passes the vertical line test.
For any given value of x in the domain, there is
one and only one value of y in the range.
There is a restriction on the value of x
x+5 ≥0
x ≥ -5
What if x = -4
√(x+5) = √1 = 1 or -1
This is not a function since there is a value of
x that has 2 corresponding values of y
Andrew M.
Ref the sideways parabola opening to the right:
In a quadratic where the square term is y instead of x
the parabola opens left or right.
y2 = x+5
x = y2 - 5
x = y2 + 0y - 5
f(y) = y2 + 0y - 5
Vertex (-b/2a, f(-b/2a))
a = 1, b=0, c = -5
-b/2a = 0/2 = 0
f(0) = -5
So when y = 0, x = -5 and the vertex is at (-5,0)
and it opens to the right since a>0
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08/29/17
Andrew M.
08/29/17