We are given the system of equations -:
![\large{ \begin{cases} 2x + 3y = - 14 \\ y = 6x + 22 \end{cases}}](/tpl/images/1382/0111/a5a51.png)
Since the second equation is y-isolated equation. It can be substituted as y = 6x+22 in the first equation.
![\large{2x + 3(6x + 22) = - 14}](/tpl/images/1382/0111/b536f.png)
Expand 3 in the expression so we can combine like terms and isolate x-variable.
![\large{2x + 18x + 66 = - 14}](/tpl/images/1382/0111/0b58a.png)
Then combine like terms.
![\large{20x + 66 = - 14}](/tpl/images/1382/0111/d7e13.png)
Get rid of 66 from the left side by subtracting both sides by itself.
![\large{20x + 66 - 66 = - 14 - 66} \\ \large{20x = - 80}](/tpl/images/1382/0111/03fd2.png)
To finally isolate the variable, divide both sides by 20 so we can leave x only on the left side.
![\large{ \frac{20x}{20} = \frac{ - 80}{20} }](/tpl/images/1382/0111/b22bf.png)
Simplify to the simplest form.
![\large{x = - 4}](/tpl/images/1382/0111/2a6bc.png)
Normally, we have to find the y-value too but since we only find x-value. The answer is x = -4.
Answer
x = -4
I hope this helps! If you have any questions or doubts regarding my answer, explanation or system of equations, feel free to ask!