Solving Quadratic Equations: Quadratic Formula — Quiz
Question 8 • Algebra I
Rhett is solving the quadratic equation 0=x2−2x−3 using the quadratic formula. Which shows the correct substitution of the values a, b, and c into the quadratic formula? Quadratic formula: x is equal to the fraction with numerator negative b plus or minus square root of b squared minus 4 A c end root and denominator 2 A
Answer
A
the fraction with numerator negative 2 plus or minus square root of negative 2 squared minus 4 1 negative 3 end root and denominator 2 times 1
B
the fraction with numerator 2 plus or minus square root of negative 2 squared minus 4 1 negative 3 end root and denominator 2 times 1
C
the fraction with numerator negative 2 plus or minus square root of negative 2 squared minus 4 1 negative 3 end root and denominator 2 times 1
D
the fraction with numerator 2 plus or minus square root of negative 2 squared minus 4 1 negative 3 end root and denominator 2 times 1
Explanation
In 0 = x² − 2x − 3, the coefficients are a = 1, b = −2, and c = −3. Substituting gives −b = 2, so the numerator begins with 2, while the denominator is 2(1) and the radicand is (−2)² − 4(1)(−3). Choice B shows this substitution; choice D appears to show the same expression.
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