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 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 Ecuación de una recta Equation of a line (from graph) Quadratic function Posición relativa de dos rectas Asymptotes Limits Distancias Continuity and discontinuities
 Sine Cosine Tangent Cosecant Secant Cotangent Trigonometric identities Law of cosines Law of sines
 Ecuación de una recta Posición relativa de dos rectas Distancias Angles in space Inner product

 Proportions Proportion An equation in which two ratios are equal is called a proportion. Two ratios and are a proportion when Remember the two ratios are equals if their cross products are equal a·d = b·c You can also use the cross product to find a missing number: Solve: $\frac{-5}{2}=\frac{t}{-8}$$\fs2(-5)(-8)=2t\;\Rightarrow\;\;40=2t\;\Rightarrow\;2t=40\;\Rightarrow\;\;t=20$ Find x to get a proportion $\frac{10}{12}=\frac{x}{6}$. Find x to get a proportion: $\frac{x}{18}=\frac{42}{108}$ Solution x=