What is the strategy for 29 +31
2 answers:
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(3 + 
) × (3 - )
Take the special case
(a - b)×(a + b)=a² - b²
a = 3
b =
3² - ()² {(√)² = the number itself}
9 - 5
4
Take the special case
(a - b)×(a + b)=a² - b²
a = 3
b =
3² - (
9 - 5
4
