Which equation is an identity? a. 8 - (5x+2) = - 5x-6 b. 7z+10-z=8z-2 (z-5) c. 8m-4=5m+8-m d. 6y+5=6y-5

Basically it simplifies to a=a or a true statement

distribute

A.

8-1 (5x+2) = - 5x-6

8-5x-2=-5x-6

-5x+6=-5x-6

6=-6

false

not an identiy

B.

7z-z+10=8z-2 (z-5)

6z+10=8z-2z+10

6z+10=6z+10

true

it's an identity

C.

8m-4=5m-m+8

8m-4=4m+8

minus 4m both sides

4m-4=8

add 4

4m=12

not an identity since both sides don't end up like 12=12 or m=m

D.

6y+5=6y-5

minus 6y both sides

5=-5

false

not an identiy

answer is B

B would be the answer