Question

This is something about absolute value but i have no idea how to do it

Answer 1

You're looking for an inequality of the form $|t-b|\le a$, or $-a\le t-b\le a$, or $b-a\le t\le b+a$.

Start with

$350^\circ\le t\le400^\circ$

Notice that 375º is the midpoint of this interval of temperatures. If we subtract all sides by 375º, then we get

$-25^\circ\le t-375^\circ\le25^\circ$

so we can set $a=25^\circ$ and $b=375^\circ$, and we can rewrite this inequality in terms of absolute values as

$|t-375^\circ|\le25^\circ$