-3 + 7x = -12
First, simplify -3x + 7x to get 4x. / Your problem should look like: 4x = -12
Second, divide both sides by 4. / Your problem should look like: x =
Third, simplify

to 3. / Your problem should look like: x = -3
Answer:
x = -3
What do you need help with
Answer: ? = -22.5
Step-by-step explanation:
Using a negative number to replace the ? turns the minus into a plus sign.
-21 - (-22.5) = 1.5 is the same as -21 + 22.5 = 1.5