show that root 11 + root 7 is irrational

1.	show that root 11 + root 7 is irrational
Answer» √11+√7Let, a= √11+√7a= √11+√7a-√11=√7(a-√11)²=(√7)²a²-2√11a+11²=49a² -2√11a+121 = 49a²-2√11a+121-49=0a²-2√11a+72=0but √11 is irrational numberso √11+√7 is an irrational number

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