Fun word problem that is almost a brain teaser. Watch the next lesson: https://www.khanacademy.org/math/algebra/solving-linear-equations-and-inequalities/More-equation-practice/v/patterns-in-sequences-1?utm_source=YT&utm_medium=Desc&utm_campaign=AlgebraI Missed the previous lesson? https://www.khanacademy.org/math/algebra/solving-linear-equations-and-inequalities/More-equation-practice/v/basic-rate-problem?utm_source=YT&utm_medium=Desc&utm_campaign=AlgebraI Algebra I on Khan Academy: Algebra is the language through which we describe patterns. Think of it as a shorthand, of sorts. As opposed to having to do something over and over again, algebra gives you a simple way to express that repetitive process. It's also seen as a "gatekeeper" subject. Once you achieve an understanding of algebra, the higher-level math subjects become accessible to you. Without it, it's impossible to move forward. It's used by people with lots of different jobs, like carpentry, engineering, and fashion design. In these tutorials, we'll cover a lot of ground. Some of the topics include linear equations, linear inequalities, linear functions, systems of equations, factoring expressions, quadratic expressions, exponents, functions, and ratios. About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content. ... https://www.youtube.com/watch?v=uA3m8vbd2wc Note: All Khan Academy content is available for free at (www.khanacademy.org)

More free lessons at: http://www.khanacademy.org/video?v=LiPQuOFVHl4 ... https://www.youtube.com/watch?v=LiPQuOFVHl4 Note: All Khan Academy content is available for free at (www.khanacademy.org)

When and why you can't invert a matrix. Practice this lesson yourself on KhanAcademy.org right now: https://www.khanacademy.org/math/precalculus/precalc-matrices/inverting_matrices/e/matrix_inverse_3x3?utm_source=YT&utm_medium=Desc&utm_campaign=Precalculus Watch the next lesson: https://www.khanacademy.org/math/precalculus/precalc-matrices/matrix-equations/v/matrix-equations-systems?utm_source=YT&utm_medium=Desc&utm_campaign=Precalculus Missed the previous lesson? https://www.khanacademy.org/math/precalculus/precalc-matrices/inverting_matrices/v/inverting-matrices-part-3?utm_source=YT&utm_medium=Desc&utm_campaign=Precalculus ... https://www.youtube.com/watch?v=UqyN7-tRS00

Introduction to the mechanism for the aldol reaction. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/science/organic-chemistry/ochem-alpha-carbon-chemistry/aldol-condensation-jay/v/aldol-condensation?utm_source=YT&utm_medium=Desc&utm_campaign=organicchemistry Missed the previous lesson? https://www.khanacademy.org/science/organic-chemistry/ochem-alpha-carbon-chemistry/formation-of-enolate-anions/v/kinetic-and-thermodynamic-enolates?utm_source=YT&utm_medium=Desc&utm_campaign=organicchemistry Organic Chemistry on Khan Academy: Carbon can form covalent bonds with itself and other elements to create a mind-boggling array of structures. In organic chemistry, we will learn about the reactions chemists use to synthesize crazy carbon based structures, as well as the analytical methods to characterize them. We will also think about how those reactions are occurring on a molecular level with reaction mechanisms. Simply put, organic chemistry is like building with molecular Legos. Let's make some beautiful organic molecules! About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content. ... https://www.youtube.com/watch?v=3XiHrsZNZko Note: All Khan Academy content is available for free at (www.khanacademy.org)