Solve the following expression:
?−(−12)=−40 \text{?}-(-12)=-40 ?−(−12)=−40
Note the following rule:
−(−x)=+ -(-x)=+ −(−x)=+
We must rewrite the exercise in the appropriate form:
?+12=−40 ?+12=-40 ?+12=−40
Next, we will add -12 to both sides to cancel out the left side:
?+12−12=−40−12 ?+12-12=-40-12 ?+12−12=−40−12
This leaves us with:
?+0=−52 ?+0=-52 ?+0=−52
?=−52 ?=-52 ?=−52
−52 -52 −52