Complicated Rational Expressions 

Sal, thank you so much for renewing my faith in math teachers! I was literally so confused in class, I felt like shoving a desk, because I couldn't understand what my teacher was saying (Plus, fractions inside fractions just look like a crime against nature :p ) But I watched your video once, and just banged out the homework in 10 minutes. You rock, dude! :D ~Pheebs :3

Negative 6 at 6:04, Sal, my old buddy.

Him writing with a mouse is neater than me with a pen. LOL

I'd like to add that the divisor in the original function (1/4 - 9/x^2) may also not be 0. Thus x^2 is not equal to 36, which amounts to +6 and -6.

thank you. i was about to go crazy because the other youtube vids wasn't helping and I wasn't understanding such simple math

X can be all the real numbers exept -6 not 6

Should the domain be all real numbers except for NEGATIVE 6 not 6 ? or am i missing something.

This helped SO much. Much Much better than my teacher. THANK YOU!!

@Oh4Chrissake yes negative 6, but positive 6 should be there as well when we assume that x is not equal to 0, all and all good tutorial

love these videos they help me so much for my honors tests!!

You're the best, THANK YOU

I love you! Algebra 2 test tomorrow. Thanks!

Omg thank you I been looking for this video

thanks Sal

Why not just find a common denominator for all the fractions in the problem (4x^2) and multiply every single term (numerator and denominator) by that LCD, thus killing off all of the “mini-denominators.” Then factor and reduce what’s left. Quicker, I think.

I got it up till it started talking about domains.

I think you mean x can't be equal to -6

@manq211 Sal was stating what x CAN'T be i.e. what is NOT in the domain of x. He wrote 6 when he meant -6. 6 is not even relevant.

x = u^3 is the result when u cube the equation u=x^1/3

Why is there a common denominator of 4x2 @3:00?

this was fun

Rational expressions are ratios of two polynomials and polynomials can't have a variable denominator which makes the equation you worked on invalid!

hi i was hoping you could help me with a problem my teacher did for us i was following him for the most part but got confuse on one small detail. the problem is this: x^(2/3) - x^(1/3) - 6 = 0; we used u replacement method to solve. so we let u= x^(1/3) and u^2=x^(2/3) and x=u^3. for the life of me i cant figure out how he got x= u^3 please explain to me how he got it

Can someone explain how x - 4 - 12 became (x - 6)(x + 2)? That flew over my head.

yeah this one is a tough one to grasp. lost me at 0 :41

Eowo

I am such a failure in math I NEED HELP PLEASE!!!😭😖😖

im only 12