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13 votes
Use the discriminant to find the number of real solutions of the equation
3x 2 -5x +4=0

User Kegn
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1 Answer

12 votes
12 votes

Answer:

zero real solutions

Explanation:

You want the number of real roots of 3x² -5x +4 = 0 and determined by using the discriminant.

Discriminant

The discriminant of a quadratic equation ax²+bx+c=0 is ...

d = b² -4ac

When d < 0, both roots are complex. When d = 0, there is one (repeated) real root. The number of real solutions is 2 when d > 0.

Application

For this equation, a=3, b=-5, c=4, so the discriminant is ...

d = b² -4ac = (-5)² -4(3)(4) = 25 -48 = -23

This means both roots are complex. There are no real solutions.

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Additional comment

As confirmation, we can look at the graph. It does not cross the x-axis, so there are no (real) values of x that make the value of the quadratic be zero.

Use the discriminant to find the number of real solutions of the equation 3x 2 -5x-example-1
User Wouter Coekaerts
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3.1k points