Question

Ratnalise dinomenater 7+3 5on 5 square root divide 7-3 5 on 5square root

Answer 1

Answer:

$7 - 3 \sqrt{5 } \times 7 - 3 \sqrt{5 } = (7 - 3 \sqrt{5} ) ^{2} = 49 + 45 - 42 \sqrt{5 } = 94 - 42 \sqrt{5} = 2(27 - 21 \sqrt{5} )\\ 7 + 3 \sqrt{5} \times7 - 3 \sqrt{5} = (7)^{2} - (3 \sqrt{5} ) ^{2} = 49 - 45 = 4$

Step-by-step explanation:

we have used (a-b)^2= a^2+b^2 - 2ab

and a^2 - b^2 = (a+b) (a-b)