Answer:
x=3
Step-by-step explanation:
4x-x=9
3x=9
x=3
Answer:
4.5 cups of spinach
Step-by-step explanation:
we know that
The recipe serves 12 people and calls for 3 cups of spinach
so
using proportion
Find out how many cups of spinach should you use, to serve 18 people

Answer: 
Step-by-step explanation: On the unit circle
1st angle = 3x
2nd angle = x
3rd angle = 65 +x
3x + x +65+x = 180
5x+65 = 180
5x=115
x = 115/5 = 23
2nd angle = 23 degrees
1st angle = 23 x 3 = 69 degrees
3rd angle = 65 +23 = 88 degrees