ANSWER
w = 30 feet
EXPLANATION
To solve
[tex]150=2w+30+2w[/tex]
First we have to add like terms. We have two terms that contain w, so we have to add the coefficients:
[tex]150=4w+30[/tex]
Then subtract 30 from both sides of the equation:
[tex]\begin{gathered} 150-30=4w+30-30 \\ 120=4w \end{gathered}[/tex]
And finally divide both sides by 4:
[tex]\begin{gathered} \frac{120}{4}=\frac{4w}{4} \\ 30=w \end{gathered}[/tex]
The width of the garden will be 30 feet.
