The best method would be to cross-multiply. Multiply the figure on the top left with the bottom right. Then set it equal to the multiplication of the bottom left with the top right.
This would turn into:
-1(x-1)=2(x+3) Then distribute the multiplication through the parentheses.
-x+1=2x+6 Next, get all the variables on one side, and the integers on another.
2x+x=1-6
3x= -5
x= -5/3