Answer:
80 ways
Step-by-step explanation:
The first thing is to apply the Fundamental Counting Principle with two groups of items, in this case the multiplication rule is used.
In this case, what we should do is that, for every 1 main course there are 8 appetizers, but there are 10 main courses therefore:
8 * 10 = 80
There are 80 ways to combine appetizers and the main course
sum of interior angle of a triangle is 180 degree
so,
3x +7 + 2x+7 +3x+6 = 180
8x + 20 = 180
8x = 180 - 20
8x = 160
x = 160/ 8
x = 20
May it will help you
2x+4
x=55
(2x+6)+(x+9)=3x+15
3x+15=180
3x=165