Question

find the missing term of 3b2 − = -9b2 ?
-6b^2
-9b^2
-12b^2

Answer 1

3b^2 - x = -9b^2 
x = 3b^2 +9b^2

x = 12b^2

3b^2 -12b^2 = -9b^2

hope this will help you