How many x-intercepts does the graph of y = 2x^2 – 8x + 5 have?
2 answers:
A graph of the equation shows the appropriate choice to be
C. 2
_____
If you would rather, you can look at the value of the discriminant. For the equation y = ax²+bx+c, the discriminant (d) is
d = b²-4ac
For your equation, this evaluates to
d = (-8)²-4(2)(5) = 64 -40 = 24
When the discriminant is positive, the function has two real roots (2 x-intercepts). When it is zero, there is only one x-intercept, and when it is negative, there are none (the roots are complex).
C. 2
_____
If you would rather, you can look at the value of the discriminant. For the equation y = ax²+bx+c, the discriminant (d) is
d = b²-4ac
For your equation, this evaluates to
d = (-8)²-4(2)(5) = 64 -40 = 24
When the discriminant is positive, the function has two real roots (2 x-intercepts). When it is zero, there is only one x-intercept, and when it is negative, there are none (the roots are complex).
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Answer:
The answer to your question is:
Step-by-step explanation:
Data
f(x) = -2x² + 8x - 2
Process
-2x² + 8x = y + 2
-2(x² - 4x + 4) = y + 2 - 8
-2(x - 2)² = y - 6
(x - 2)² = 1/2 (y - 6)
Vertex = (2, 6)
Axis of symmetry = x = 2
y-intercept
f(0) = -2(0)² + 8(0) - 2
f(0) = 0 + 0 - 2
f(0) = -2
Domain (-∞, ∞)
Range (-∞, 6]
See the graph below
