Answer:
1) n=-12
2) y=-8
3) x= 1/30
Step-by-step explanation:
1) 7+n=-5
7+n-7=-5-7
n=-12
2) 18=-3y-6
-3y-6=18
-3y-6+6=18+6
-3y=24
-3y/-3 = 24/-3
y= -8
3) 3/5x=18
3/15 X 5x= 18 X 5x
3=90x
90x/90= 3/90
x= 1/30
Answer:
Johnny is wrong.

Step-by-step explanation:
Johnny is wrong.
A better definition would be:
is the set of all elements that belong to at least one A or B.
So, the elements that belong to both A and B, like c and d in this exercise, also belong to
.
So:
