# algebra!!!!

#### i.suck.at.math

##### New member
Replace the * symbol with the correct number to get the correct equation

#### Otis

##### Elite Member
Hi. Are you studying on your own or taking a math class? Do you have a beginning algebra textbook?

Before trying these types of exercises, one first needs to learn -- and practice -- expanding expressions (that is, multiplying out basic algebraic forms to obtain their product). Learning how to factor those products (the reverse of expanding) is also very helpful.

Does the information at the following page look familiar? It's a start.

Once we become familiar with those operations, we are then ready to learn some special product/factoring patterns. For example, your first two exercises above use a pattern discussed on the page below.

Please study the examples at those links, and then give your first exercise a try. If you have any questions about what you've read, be sure to let us know. Otherwise, show us how far you can get. Thank you!

#### HallsofIvy

##### Elite Member
$$\displaystyle (a+ b)^2= a^2+ 2ab+ b^2$$
Compare your $$\displaystyle 4x^2+ 12xy+ 9y^2$$ with that.
What is "a" and what is "b"?

$$\displaystyle (a- b)^2= a^2- 2ab+ b^2$$
Compare your $$\displaystyle 9n^2- *+ 25m^2$$ with that.
What is "a" and what is "b" and what is that "*"?

#### Jomo

##### Elite Member
(2x+ *)^2 = (2x)^2 + 2(2x)(*) + (*)^2 = 4x^2 + 4x* + *^2 = 4x^2 + 12xy + 9y^2

You need 4x* = 12xy. Divide by sides by 4x to get * = ...

#### HallsofIvy

##### Elite Member
If you have ever taken an Algebra class then one of the things that you should have learned is
$(a+ b)^2=$

#### Otis

##### Elite Member
one of the things that you should have learned is
$(a+ b)^2=$
That there's money in math?

PS: At this site, double dollars signs $$are required to invoke LaTeX. [imath]\;[/imath] #### lev888 ##### Elite Member There's money in math. PS: At this site, double dollars signs$$ are required to invoke LaTeX.

[imath]\;[/imath]
Double dollars now do what single quotes used to do?

#### Otis

##### Elite Member
Double dollars now do what single quotes used to do?
I've never seen single quotes invoke LaTeX here, but they may serve that purpose elsewhere.

The current tag options are listed in the LaTeX thread on the News board:

At this site, each line (or set of lines) of LaTeX coding must be enclosed within $$\displaystyle \text{[te}\text{x]}$$ and $$\displaystyle \text{[/te}\text{x]}$$ tags or within $$\displaystyle \text{[ma}\text{th]}$$ and $$\displaystyle \text{[/ma}\text{th]}$$ tags or within \͏[ and \͏] tags. Each of those three tag options will default to display style. If you would like to force inline style, then use the tags \͏( and \͏) or $$\displaystyle \text{[ima}\text{th]}$$ and $$\displaystyle \text{[/ima}\text{th]}$$ or $$and$$, instead.

#### Subhotosh Khan

##### Super Moderator
Staff member
Double dollars now do what single quotes used to do?
Inflation !!!