Answer: Simplifying the square roots and adding the similar square roots the answer is option c. 6 square root of 5 end root minus 4 square root of 7
Solution:
3β5-2β7+β45-β28
45=9*5 and 28=4*7. Replacing in the equation above:
3β5-2β7+β(9*5)-β(4*7)
Using β(a*b)=βaβb
3β5-2β7+β9β5-β4β7
β9=3 and β4=2. Replacing in the equation above:
3β5-2β7+3β5-2β7
Adding similar square roots:
(3+3)β5+(-2-2)β7=
(6)β5+(-4)β7=
6β5-4β7