Algebra: Chapter 7-8, p 338
Parallel and Perpendicular Lines
Parallel lines by definition have the same slope. So, for the equation of 2 lines, all we have to do is figure out what the slope is of them both. if they have the same slope, then they are parallel. Check too, however, to make sure that both lines have DIFFERENT y-intercepts. If they have the same slope and y-intercept, then they are the same line, one on top of the other.
Perpendicular lines are lines that intersect at 90° or are right angles. By definition, the slope of 2 lines that are perpendicular, when multiplied together, have a product of −1.
You MAY have to solve the equation lines for y, isolating it to see what the slope, m, is as well as the y-intercept.
Here is a link from purplemath too.
Math 8, Chapter 5-6, p 248
Solving Equations
To solve equations, these are one step equations by the way, we isolate the variable on one side and keep the constants on the other side. With decimals and fractions, its just like with whole numbers. Remember to have the decimals line up of the fractions with the same common denominator. That is all there is, pretty simple.
Example:
`b +3/5 = 3/2`
Subtract `3/5` from both sides
`b +(3/5) − (3/5) = (3/2) − (3/5)`
Convert to LCD of 2*5 = 10 (or tenths): `(3/2) =(15/10)` and `(3/5)=(6/10)`, so …
`b= (15/10) − (6/10)`
Therefore, `b=9/10`