8 - 4a = -2a

7th Grade Linear Questions

a = 4

Step-by-step explanation:

So your goal here is to get the variable on just one side, so add 4a to both sides.  This cancels out the 4a on of of the sides and puts a on the other side.  The new equation is 8 = -2a + 4a.  Combine like terms to get 8 = 2a.  Divide both sides by 2 to get a = 4.    You can check your work by replacing a with 4:  

8 - 4(4) = -2(4)

8 - 16 = -8

-8 = -8

Since the final result is true, (-8 does equal -8,) a = 4.  

21

jk it's 20

step-by-step explanation:

just sum

10 + 10 = 20