McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
Preparing for Standardized Tests
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Exercise 2 Page 221

Find the discriminant.

F

Practice makes perfect
The graph of f crosses the x-axis at points where f(x)=0. In this case f(x)=2x^2-3x+2 is quadratic, so we can look at the discriminant to find the number of x-intercepts. 2 &Quadratic equation: && ax^2+ bx+ c=0 &Solutions:&&x=- b±sqrt(b^2-4 a c)/2 a &Discriminant:&& b^2-4 a c The table below summarizes the relationship between the discriminant and the number of real solutions.
Discriminant (b^2-4ac) Number of Real Solutions
Positive 2
Zero 1
Negative 0
Let's identify the coefficients in our expression. 2x^2-3x+2= 2x^2+( -3)x+ 2 We can see that a= 2, b= -3, and c= 2. Let's find the discriminant.
b^2-4 a c
( -3)^2-4( 2)( 2)
Evaluate
9-16
-7
Since the discriminant is negative, the graph has no x-intercepts. The correct answer is F.