54/12 = 4.5
sf = 4.5
so x = 2 · 4.5 = 9
"like terms" are terms whose variables (and their exponents such as the 2 in x2) are the same. in other words, terms that are "like" each other
only like terms can be combined. we combine like terms to shorten and simplify algebraic expressions, so we can work with them more easily.
3.75 * 10^-6.
1.5 * 10^3 * 2.5 * 10^-9
= (2.5*1.5) * 10^(3 + (-9)
= 3.75 * 10^-6.
a horizontal line; a melting ice cube.
a constant interval appears as a horizontal line. the graph in the interval has a slope m = 0.
here's an example of a constant interval.
you take an ice cube from the freezer and place it in a container on the counter.
the temperature of the ice cube is -5 °c. the ice cube will warm to 0 °c, and then it will start to melt. while it is melting, the temperature is constant at 0 °c.
when the ice has completely melted, the water will start warming to room temperature.
a plot of temperature vs. time would look something like the graph below.
the interval ab, where the ice is melting, is a constant interval.