# Question #3f1d2

Oct 22, 2016

$x = - \frac{10}{7}$

#### Explanation:

• Remove parentheses by distributing their coefficients:

$9 x + 4 = \textcolor{red}{2 \left(x - 1\right)} - 4$

$9 x + 4 = \textcolor{red}{2 x - 2 \left(1\right)} - 4$

$9 x + 4 = 2 x - 2 - 4$

• Gather all terms containing $x$ on the left hand side of the equation, and all other terms on the right hand.

$9 x + \textcolor{red}{4} = \textcolor{b l u e}{2 x} - 2 - 4$

$9 x + \cancel{4} \cancel{\textcolor{red}{- 4}} \textcolor{b l u e}{- 2 x} = \cancel{2 x} - 2 - 4 \textcolor{red}{- 4} \cancel{\textcolor{b l u e}{- 2 x}}$

$9 x - 2 x = - 2 - 4 - 4$

• Combine like terms.

$\left\{\begin{matrix}9 x - 2 x = 7 x \\ - 2 - 4 - 4 = - 10\end{matrix}\right.$

$\implies 7 x = - 10$

• Divide both sides by the coefficient of $x$ to isolate $x$.

$\textcolor{red}{7} x = - 10$

$\frac{7 x}{\textcolor{red}{7}} = \frac{- 10}{\textcolor{red}{7}}$

$x = - \frac{10}{7}$