Question

find the value of a: 79² - 1 =(a - 1) ( a + 1)​

Answer 1

79² - 1 = 79² - 1² [(a + b)(a - b) = a² - b²]

79² - 1² = [(79 + 1)(79 - 1)]

[(80)(78)]

80 × 78

6240

Hope it helps you, hv a nyc day

Answer 2

Step-by-step explanation:

79²-1 = (a+1)(a-1) since, (a+b)(a-b)= a²-b²

79²-1² = a²-1²

79² = a² -1² +1²

79² = a²

a² = 79²

a = √79²

hence, a = 79

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