Use the Fundamental Theorem of Algebra to determine which of the following equations have two solutions. Explain your reasoning in 3–5 sentences.

a. −9x+4x2+3=0

b. −2x2−5=0

c. 57x2=0

d. 0x2+7x−2=0

e. 0x3−x2+2x+4=0

1 answer

The Fundamental Theorem of Algebra states that a polynomial of degree \( n \) will have exactly \( n \) roots in the complex number system, counting multiplicities. Let's analyze each equation:

a. \( -9x + 4x^2 + 3 = 0 \) is a quadratic (degree 2) polynomial, which has 2 solutions (could be real or complex).

b. \( -2x^2 - 5 = 0 \) is also a quadratic (degree 2) polynomial. Thus, it has 2 solutions as well.

c. \( 57x^2 = 0 \) is again a quadratic (degree 2) but only has 1 unique solution (a double root at \( x = 0 \)).

d. \( 0x^2 + 7x - 2 = 0 \) simplifies to a linear equation (degree 1), which has 1 solution.

e. \( 0x^3 - x^2 + 2x + 4 = 0 \) simplifies to a quadratic (degree 2) polynomial, which has 2 solutions.

The equations that have two solutions are (a), (b), and (e).