Most chordates are vertebrates. Invertebrate chordates, which belong to two of the subphyla of chordatesâCephalochordata and Urochordata, also have a dorsal tubular nerve cord, a notochord, pharyngeal pouches, a postanal tail, and, possibly, an ancestral thyroid gland.They ha ve no backbone, however.ost chordates are vertebrates. Invertebrate chordates, which belong to two of the subphyla of chordatesâCephalochordata and Urochordata, also have a dorsal tubular nerve cord, a notochord, pharyngeal pouches, a postanal tail, and, possibly, an ancestral thyroid gland. They ha ve no backbone, however.
Quadratic Equation. An equation where the highest exponent of the variable (usually x) is a square (2). It is usually written ax2+bx+c = 0 Example: 2x2+5x-3 = 0. See: Exponent. Quadratic Equations.
One simple way to solve quadratic equations is to set each factor equal to zero and then solve for each factor. However, when the quadratic equation is difficult to solve, the quadratic formula is used to find the solutions.