Absolute Inequation? (1 Viewer)

[MrBrightside]

1 - x^2 less than or equal to 0

i'm am confused as to why the sign changes when only subtraction occurs??

the ans is x less than or equal to -1, x greater than or equal to 1

how do you do this? ive tried factorisation, but i dunno how it connects to the ans.

 

[AAEldar]

Put everything on the other side. The sign doesn't change if you're adding or subtracting, only when multiplying or dividing by a negative.

Factorise it to get the difference of two squares of (x-1)(x+1). Then x is either 1 or -1.

Put it on a number line, and test.

 

[MrBrightside]

Put everything on the other side. The sign doesn't change if you're adding or subtracting, only when multiplying or dividing by a negative.

Factorise it to get the difference of two squares of (x-1)(x+1). Then x is either 1 or -1.

Put it on a number line, and test.

umm i think that's incorrect

the xs r meant to be on the other side...

(1- x)(1+x) less than or = 0

 

[hscishard]

Plot 1 and -1 on number line. Use the test points. You will find it's x=>1 or x<=-1

 

[MrBrightside]

Plot 1 and -1 on number line. Use the test points. You will find it's x=>1 or x<=-1

ahh I seee...thx

 

[AAEldar]

Plot 1 and -1 on number line. Use the test points. You will find it's x=>1 or x<=-1

Yea that's what I was saying, just didn't use Latex >.<

 

[ohexploitable]

Graphing method is so much better IMO...

 

[mirakon]

Yeah, eventually you'll get so used to it though you can pretty much know intuitively for quadratics.