Math Reflection p. 45

1. An equation of the form y=mx+b has two variables (x and y), a y-intercept (b), and a coefficient of x (m). A y-intercept is the point where the line crosses the y axis or on a table when x is at 0. A coefficient of x is the number that multiplies x. For example, in the equation y=5x+20, 5 is the coefficient and 20 is the y-intercept.

2. a. A table can be used to solve a problem for a linear relationship. If you have what x equals you look at that number under x in the table, and next to it will show you what y equals, or vise versa. A graph can be used to solve a problem for a linear relationship. If you have what y equals, you look at that number on the y axis, then go to the right until you reach the line and look down from that point to find x, and vise versa.

b. To use an equation to solve a problem first write the equation. Then fill in the variables you know.If the equation is set up like y=mx+b, and you know the y, next you would subtract the y-intercept (b) from each side. Then divide each side by he coefficient (m) and you will end up with your answer. For example if y= 40:

y=5x+20
40=5x+20
-20 -20
20=5x
/5 /5
4=x

If you know x, you would simply solve the equation. For example if x=8:

y=5x+20
y=5(8)+20
y=40+20
y=60