1. Explain how to find the slope of a line from a table of data.

Question

A: ?

2. Explain how to justify the Cross Products Property by using Mulitplication Property of Equality.

A: ?

Answer 1

Let's say this is your table:
x y
0 1
1 3
2 5

Plot those points on a graph. Now, notice when you move on the x number line from 1 to 2 you're moving up 2 spaces. That means your slope is 2 and when x = 0, what does y=? That's your intercept.

So, the standard form of that table would be y = 2x+1 or y=slope times x plus the intercept.

Hope that helps.

Answer 2

In answer to the other question, first we need to know:

The Multiplication Property of Equality states that if you multiply both sides of an equation by the same number, the sides remain equal (i.e. equality is preserved).

and

Cross Product Property states that in a proportion, product of the means is equal to the product of the extremes.

So, per the Cross Product property:
A = C
B D
Now, multiply both sides by B. You get AB over B which is A and CD over D. So now you have A=CB/D
Now multiply both sides by D. You get AD = CBD over D which is the same as AD = CB.
Ta-dah!