Basic Math Examples

$21 = - b - 6 b$

Step 1

Rewrite the equation as $- b - 6 b = 21$ .

$- b - 6 b = 21$

Step 2

Subtract $6 b$ from $- b$ .

$- 7 b = 21$

Step 3

Divide each term in $- 7 b = 21$ by $- 7$ and simplify.

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Step 3.1

Divide each term in $- 7 b = 21$ by $- 7$ .

$\frac{- 7 b}{- 7} = \frac{21}{- 7}$

Step 3.2

Simplify the left side.

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Step 3.2.1

Cancel the common factor of $- 7$ .

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Step 3.2.1.1

Cancel the common factor.

$\frac{- 7 b}{- 7} = \frac{21}{- 7}$

Step 3.2.1.2

Divide $b$ by $1$ .

$b = \frac{21}{- 7}$

Step 3.3

Simplify the right side.

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Step 3.3.1

Divide $21$ by $- 7$ .

$b = - 3$