solve quadratic equation by square root property

solve quadratic equations of the type ax^2+b=k and (ax+b)^2=k using the square root property

Category:

Education

Tags:

• algebra
• quadratic
• equation
• square
• root
• property

[TheOneAndOnlyKinable]

WOW HOW DO YOU SOLVE A THREE STEP OMG EVERYONE IS DOING EASY EQUATIONS ON HERE WOW, can someone plz do x^2 + 6x - 7 = 0 by square root plzzz.

[robichaudd]

@TheOneAndOnlyKinable Search for a video on "solve quadratic equation by completing the square." At some point in the process the square root property is used. I think that might be what you're looking for.

[mrhamada56]

can you do the question x^2 -2x+5=0, im kind of stuck there. I have to solve for complex roots

[robichaudd]

@mrhamada56 Sorry but I only have time to answer follow up questions to the problems in the video. Keep searching youtube - there must be some videos out there for solving quadratic equations with complex solutions.

[jwm239]

...I assume that "principal" square root

does not apply since these roots are

solutions of quadratic equations, not

constants (e.g., square root of 9 is 'only'

three and not also -3).

[robichaudd]

That's correct. For something like x^2=9 we can also see how we need both +3 and -3 as solutions by solving it by factoring instead:

x^2=9 ... x^2-9=0 ... (x+3)(x-3)=0 ... x=-3,3

[wove212]

thank you so much! i understood more from watching this video than struggling with the text book for the past few hours!

[rockingmonster12]

hey girl you much be some sort of good teacher. u've helped me alot thanks alot!!!!!!!!

[Stealthrellik]

STRESSED NO MOAR, thank you :D

[joanaguilarify]

Is it me or she sounds like sara quin..?

[clearelite]

Excellent lesson and very concise explanation, thanks^9000!

[justkatt29]

you just saved me from having a panic attack thank you

[TarelaEye]

@TheOneAndOnlyKinable move the 7 on to the other side then do her process sorry im 10 months late :p

[TheLoveformankind]

U R BEST TEACHER

[jh3835]

@robichaudd ahhh yes. i got it, thanx. i had some equations using the square root property and while solving for sqrt, i would get an error on my calculator. this drove me nuts, i found out that i have to factor out an (i) for the negative sqrts. we covered this, i just got a little overwhelmed.

[jh3835]

@ 3:38 there are times when your answer has an i on the end...ex: plus or minus 7i. why is that...?

[warmsaltybutthole]

The square root of 36 is 6

[Captain5337]

Ok, I have a question: I've got this problem --> (x+7)² = -36 and the next step I've been taught to take is to then have x+7 = +/- √36 but I don't know what to do with the √36. Would the equation then be x+7 =+/- 2√3?