4 − 2x ≤ 3/2

Add 2X to both sides
4≤3/2+2X
Subtract 3/2 from both sides
4-3/2≤2X
Convert 4 to whole fraction then multiply straight across to turn into a like term.
4/1-3/2, 12/2-3/2=9/2, 9/2≤2X
Divide both sides by 2, when dividing a fraction you invert and multiply, so (9/2)/(2/1) becomes (9/2)*(1/2)=9/4
9/4≤X

X is greater than or equal to 9/4ths, which is 2 and 1/4th.