1) (x - 7) + x = 33;

x - 7 + x = 33;

x + x = 33 + 7;

2x = 40;

x = 40 : 2;

x = 20;

2) x + (x - 1) = 40;

x + x - 1 = 40;

2x = 41;

x = 20.5