Use the fundamental theorem of algebra to determine which of the following equations have two solutions. Explain reasoning in 3 sentences.

a. -9x+4x^2+3=0
b. -2x^2 -5=0
c. 5/7 x^2=0
d. 0x^2 + 7x-2=0
e. 0x^3 -x^2 +2x+4=0

1 answer

The fundamental theorem of algebra states that a polynomial of degree \( n \) will have exactly \( n \) roots (solutions), considering multiplicity and complex numbers.

a. The equation \(-9x + 4x^2 + 3 = 0\) is a quadratic equation (degree 2) and will have exactly 2 solutions.
b. The equation \(-2x^2 - 5 = 0\) is also a quadratic equation (degree 2), which means it also has 2 solutions.
c. The equation \(\frac{5}{7}x^2 = 0\) is quadratic with a degree of 2, hence it has 2 solutions, but both are the same (x = 0 has multiplicity 2).
d. The equation \(0x^2 + 7x - 2 = 0\) is linear (degree 1), so it has exactly 1 solution.
e. The equation \(0x^3 - x^2 + 2x + 4 = 0\) can be simplified to \(-x^2 + 2x + 4 = 0\) which is also quadratic (degree 2), thus it has 2 solutions.

In summary, the equations that have two solutions are a, b, and e.