Answer
The answer and procedures of the exercise are attached in the following archives.
Explanation
You will find the procedures, formulas or necessary explanations in the archive attached below. If you have any question ask and I will aclare your doubts kindly.
I believe it would be b= -264
(I’m not 100% sure though so you might wanna check)
(2x - 5)° + 45° = 180°
2x° + (-5 + 45)° = 180°
2x° + 40° = 180°
2x° = 180° - 40°
2x° = 140°
x° = 140 ÷ 2
x° = <u>7</u><u>0</u><u>°</u>
So, the value of x is 70°
<em>Hope it helps and is useful</em><em> </em><em>:</em><em>)</em>