Question

Using suitable identity find value of 99X99​

Answer 1

★ question

★★★using suitable identity find the value of 90 x 90

✈︎✈︎> let's find out

✈︎✈︎using identity (I)

✈︎✈︎(a+b)=a²+2ab+b²

✈︎(90+9) (90+9)

✈︎(90+9)²= 90²+2(90)(9)+9²

✈︎(90+9)²= 8100+1620+81

✈︎(90+9)²= 9801

✈︎hence the value of 90×90 is 9801

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identities:-

(a+b)²=a²+2ab+b²

(a-b)²=a²-2ab+b²

(a+b)(a-b)=a²-b²