Sal shows how to factor the expression 4x+18 into the expression 2(2x+9).
Introduction to scientific notation. An in-depth discussion about why and how scientific notation is used.
Learn how to rewrite expressions with negative exponents as fractions with positive exponents. A positive exponent tells us how many times to multiply a base number, and a negative exponent tells us how many times to divide a base number. We can rewrite negative exponents like x⁻ⁿ as 1 / xⁿ. For example, 2⁻⁴ = 1 / (2⁴) = 1/16.
The molar mass of a substance is the mass in grams of 1 mole of the substance. As shown in this video, we can obtain a substance's molar mass by summing the molar masses of its component atoms. We can then use the calculated molar mass to convert between mass and number of moles of the substance.
Sal shows how to find the slope of a line.
Functions assign outputs to inputs. The domain of a function is the set of all possible inputs for the function. For example, the domain of f(x)=x² is all real numbers, and the domain of g(x)=1/x is all real numbers except for x=0. We can also define special functions whose domains are more limited.
Sal introduces equivalent fractions with pizza.
Sal factors 4y^2+4y-15 as (2y-3)(2y+5) by grouping.
A gene as a stretch of DNA on a chromosome. Alleles as versions (sequence variants) of a gene.