1) Only 2
1) Examining the expressions we have
1. -5/8+3/5 =-1/40 Rational Expression
2. 1/2+ √2 Irrational Expression
3.(√5)×(√5)= 5 Rational Expression
4. 3×(√49) = 21 Rational Expression
2) Since √2 is an irrational number √2 = 1.4142.... non-periodic and infinite number, and number added to it will yield an irrational number.
3) So the answer is 1) Only 2