Answer:
a - b
Step-by-step explanation:
Assuming you mean: [tex](a^\frac12-b^\frac12)(a^\frac12+b^\frac12)[/tex]
Apply Difference of Two Squares formula [tex](a-b)(a+b)=a^2-b^2[/tex]:
[tex]\implies (a^\frac12-b^\frac12)(a^\frac12+b^\frac12)=(a^\frac12)^2-(b^\frac12)^2[/tex]
Apply the exponent rule [tex](a^b)^c=a^{bc}[/tex] :
[tex]\implies (a^\frac12)^2-(b^\frac12)^2=a^1-b^1=a-b[/tex]