-38b+b-(-7b)+(-9)=21

Solution for -38b+b-(-7b)+(-9)=21 equation:

Simplifying
-38b + b + -1(-7b) + (-9) = 21

Remove parenthesis around (-7b)
-38b + b + -1 * -7b + (-9) = 21

Multiply -1 * -7
-38b + b + 7b + (-9) = 21
-38b + b + 7b + -9 = 21

Reorder the terms:
-9 + -38b + b + 7b = 21

Combine like terms: -38b + b = -37b
-9 + -37b + 7b = 21

Combine like terms: -37b + 7b = -30b
-9 + -30b = 21

Solving
-9 + -30b = 21

Solving for variable 'b'.

Move all terms containing b to the left, all other terms to the right.

Add '9' to each side of the equation.
-9 + 9 + -30b = 21 + 9

Combine like terms: -9 + 9 = 0
0 + -30b = 21 + 9
-30b = 21 + 9

Combine like terms: 21 + 9 = 30
-30b = 30

Divide each side by '-30'.
b = -1

Simplifying
b = -1