help me right here guys

[Anonymous No.11511046]

got the following inequation sequence:

[math]-10 \leq x \leq 12 \Leftrightarrow[/math]
[math]-10+5 \leq x+5 \leq 12+5 \Leftrightarrow[/math]
[math](-5)^2 \leq (x+5)^2 \leq 17^2 \Leftrightarrow[/math]
[math]25+3 \leq (x+5)^2+3 \leq 289+3
\Leftrightarrow[/math]
[math]28 \leq (x+5)^2+3 \leq 292[/math]

I'm thinking that the error here is that, when you start to do [math](x+5)^2+3 \leq 292[/math] you eventually end up in [math]x^2+10x \leq 264[/math] which is a quadratic inequation, therefore it gives you two values for [math]x[/math], is this correct?

if not, pls explain i'm a brainlet

[Anonymous No.11511047]

btw, the exercise marks that there's an error here, and that's what i have to find

[Anonymous No.11511049]

>>11511046
Second passage is highly illegal. Consider, for example, [math]x = -5[/math], then we have that [math]0 \geq 25[/math].
Also, ask this stuff in /sqt/.