Math Help

Archive for July, 2010

Question: Discrete math question about sets?

I’m running through some homework and am stuck on a problem:

What can you say about the sets A and B if the following are true?

(a) A – B = A

(b) A – B = B – A

I don’t understand at all what sort of answer I’m supposed to give to these two questions and would appreciate help.

Answer: (a) A – B = A

You can say that no elements of A are in B, and that no elements in B are in A. I believe there’s a name for this property of a set, although currently I forget what it is.

(b) A – B = B – A
A – B = B – A
B and A are the exact same set, you can use a Venn diagram to confirm this, and it is a property of sets used to prove that sets are equal.

Stem-and-Leaf Plots – YourTeacher.com – Pre Algebra Help

Question: Help with pre algebra math?

Sorry if it looks really simple, I started school yesterday and I’m a little empty minded about this. We’re just doing pre algebra to warm u[ before going on to Algebra. I only want to know how to, I’m not actually looking for answers:
1. State the first step in solving each equation
ex: 2b+9=3 (and also with it leading to a negative)
ex:4b-6= -18

2. Actually solve each equation:
ex 1: 2d-8= -10
ex 2: 9x-15=39

Answer: What you have to do is get the variables which are the “x” and “d” on one side of the equation.

For example, 2b + 9 = 3
what you do first is try to get 2b by itself, so you do:

2b + 9 = 3
– 9 -9

2b = – 6

the next step you do is you divide 2b into – 6 to get the answer:

2b / 2 = -6/2

Therefore, the answer would be b = – 3

I hope this helps! If it doesn’t I’m sure you can find plenty of websites that can help you with this, plus youtube probably has a couple of videos on this too.

Math Combinations – YourTeacher.com – Pre Algebra Help

Cubic equations are equations in the following form. The highest power of x in cubic equations is 3, meaning that the coefficient a of x cube cannot be zero. If a is zero then the equation is not a cubic equation. Below are roots of cubic equations. Roots of cubic equations are useful in solving cubic equations and factoring cubic equations. We will deal with how to solve cubic equations and step by step cubic equations in another section. For this section, we introduce cubic equations and the roots of cubic equation formulas.

Cubic equations can be written in the above form.

Roots of cubic equations

When solving cubic equations, if the roots of the cubic equation are given by:

Then the following Math Formulas are true for the cube roots of the cubic equation.