Answer:
Equation: x-(-2)=21
Solution: x=19
Step-by-step explanation:
A number decreased by -2 is equal to 21.
Let's call the number,x. Decreased means we are going to subtract.
x-(-2)=21
-(-2) is just +2:
x+2=21
Subtract 2 on both sides:
x=21-2
Simplify:
x=19
So if 19 is decreased by -2 we should get 21.