21=-b-6b
Rewrite the equation as -b-6b=21.
-b-6b=21
Subtract 6b from -b.
-7b=21
Divide each term in -7b=21 by -7.
-7b-7=21-7
Cancel the common factor of -7.
Cancel the common factor.
-7b-7=21-7
Divide b by 1.
b=21-7
b=21-7
Divide 21 by -7.
b=-3
b=-3
Solve for b 21=-b-6b