$5 - 2x = 3 - 2\left(x + 5\right) - 1$
Apply the distributive property$5 - 2x = 3 - 2x - 2 \cdot 5 - 1$
Multiply $ - 2$$5 - 2x = 3 - 2x - 10 - 1$
Subtract $10$$5 - 2x = - 2x - 7 - 1$
Subtract $1$$5 - 2x = - 2x - 8$
Add $2x$$5 - 2x + 2x = - 8$
Add $ - 2x$$5 + 0 = - 8$
Add $5$$5 = - 8$