Answer:
x=-1
Step-by-step explanation:
Answer
Subtract
from 
then;

Remove the bracket we have;

Like terms are those terms which have same variable to the same power.
Combine like terms;

Therefore, Subtracting
from
we get 
The denominator is 40
10-3=7 (number of students in the band who do not ride the bus)
7/40=0.175
0.174*100=17.5% chance
Hope this helps!
Answer:
cos 23 = x/7.8
Step-by-step explanation: