Can someone plz help me with the first one also it will be appreciated if u could show working out too!

Answer:
Angles in a quadrilateral add up to 360°.
[tex]90 + 3x + x + 20 + 2x + 10 = 360\\ 90 + 20 + 10 + 3x + x + 2x = 330\\ 120 + 6x = 360 \\ 6x = 360 - 120 \\ 6x = 240 \\ x = \frac{240}{6} \\ x = 40[/tex]
[tex]3x = 3 \times 40 = 120 \\ [/tex]
[tex]x + 20 = 40 + 20 = 60[/tex]
[tex]2x + 10 = 2 \times 40 + 10 = 80 + 10 = 90[/tex]
Difference between largest & smallest angles =
[tex]120 - 60 \\ = 60[/tex]
60 is the difference the largest & the smallest angle.