  • Matrices
• Algebra
• Geometry
• Funciones
• Trigonometry
• Coordinate geometry
• Combinatorics
 Suma y resta Producto por escalar Producto Inversa
 Monomials Polynomials Special products Equations Quadratic equations Radical expressions Systems of equations Sequences and series Inner product Exponential equations Matrices Determinants Inverse of a matrix Logarithmic equations Systems of 3 variables equations
 2-D Shapes Areas Pythagorean Theorem Distances
 Graphs Definition of slope Positive or negative slope Determine slope of a line EcuaciÃ³n de una recta Equation of a line (from graph) Quadratic function PosiciÃ³n relativa de dos rectas Asymptotes Limits Distancias Continuity and discontinuities
 Sine Cosine Tangent Cosecant Secant Cotangent Trigonometric identities Law of cosines Law of sines
 EcuaciÃ³n de una recta PosiciÃ³n relativa de dos rectas Distancias Angles in space Inner product

Slope of parallel and perpendicular lines

Parallel lines have the same slope.
Perpendicular lines have slopes that are opposite reciprocals, like and . The slopes also have a product of -1.

Line t has a slope of . Line u has a slope of . Are line t and line u parallel or perpendicular?

The lines are not parallel because and are not equal.

The lines are perpendicular because and are opposite reciprocal:

 Take the slope of line t Find the reciprocal Find the opposite

 Yes, and are opposite reciprocals.

So, the lines are perpendicular.

Line e has a slope of . Line z has a slope of . Are line e and z parallel or perpendicular?
parallel
perpendicular
neither