Ryan only work for 9 1/4 hour everyday because he takes 1 1/4 hour of break so you minus the from the total and get the sum of 9 1/4
237 654
- = -
8 x
cross multiply
5232=237x
÷237 ÷237
x=22.0759
It will take them about 22 hours
Whenever you're interested in computing the (absolute) difference between two values of a certain variable, you have to subtract the final value and the initial value. This is often written as delta:

So, in this case, the final temperature is -30°F. The initial temperature is 115°F. So, the variation is

A negative delta indicates that the value decreased, which is our case.
Angle 1 is a "corresponding angle" with respect to the one marked 155°, so it has the same measure. The measure of angle 1 is ...
... 155°
(x-1)(x-1)
=x^2-x-x+1
=x^2-2x+1
(x+7)(x-7)
=x^2-7x+7x-49
=x^2-49