The irrational numbers are the set of number which can NOT be written as a ratio (fraction). Decimals which never end nor repeat are irrational numbers. Irrational numbers are "not closed" under addition, subtraction, multiplication or division.
so (66-x)/30=(x+4)/5 times both sides by 5 (66-x)/6=x+4 times both sides by 6 66-x=6(x+4) distribute 66-x=6x+24 add x to both sides 66=7x+24 minus 24 from both sides 42=7x divide both sides by 7 6=x x=6 units
