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.
Quadratic equation: An equation in the standard form a x 2 + bx + c = 0, where a â  0 is called a quadratic equation. Quadratic formula: A quadratic formula is the solution of a quadratic equation a x 2 + bx + c = 0, where a â  0, given by. Quadratic inequality: An inequality written in one of the forms y a x 2 + bx + c,