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Fact Check: Does x^2 + 1/2x - 7.5 Have Roots 2.5 and -3?

“x^2+1/2x-7.5”
Roots: 2.5, -3
Confidence: High Checked on May 28, 2026

Summary

The quadratic x² + ½x − 7.5 = 0 has discriminant 30.25, whose square root is 5.5. Applying the quadratic formula gives x = (−0.5 ± 5.5)/2, yielding the solutions x = 2.5 and x = −3. The expression factors as (x − 2.5)(x + 3).

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Sources 60 searched

jmap.org
dl.uncw.edu
  • Solving Equations Algebraically

    So, x = 0 is not a solution. ... When we substitute x = 3 into the original equation, we get the statement 3 = 3. This is true, so x = 3 is a solution. Solution: x = 3. Note: The solution is the x-coordinate of the intersection point of the graphs of y = x and y = sqrt(x+1)+1.

math.stonybrook.edu
  • Lecture 27 Quadratic Formula

    Solution. The quadratic equation is written in the standard form ... Answer. x = 1 or x = −3 . ... Example 2. Solve the equation 2x2 −3x −1 = 0 .

math.vanderbilt.edu
  • The most common errors in undergraduate mathematics

    Beginners often make mistakes when they use "working backward," because they don't notice that some step is irreversible. For instance, the statement · x > is not true for all real numbers x. But if we didn't know that, we might come up with this proof: ... Squaring both sides of an inequality is a reversible step if both sides are nonnegative. Thus we obtain ... x." But that conclusion is wrong. The right side of the inequality is undefined when x = 0.5.

tutorial.math.lamar.edu
  • Common Math Errors

    In the first case I put parenthesis around then \(4x - 5\) and in the second I didn’t. Since we are subtracting a polynomial we need to make sure we subtract the WHOLE polynomial! The only way to make sure we do that correctly is to put parenthesis around it. Again, this is one of those errors that people do know that technically the parenthesis should be there, but they don’t put them in and promptly forget that they were there and do the subtraction incorrectly. Example 4 Convert \(\sqrt {7x} \) to fractional exponents.

khanacademy.org
content.nroc.org
openstax.org
quickmath.com

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