Question

/ это дробь
a)13^2 – 26∙3+3^2 b) 74^2 −26^2/35^2−25 .

Answer 1

a² - b² = (a - b)(a + b)
(a - b)² = a² - 2ab + b²
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1)
13² - 26*3 + 3² = 13² - 2*13*3 + 3² = (13 - 3)² = 10² = 100
2)
(74² - 26²)/(35² - 25) = (74² - 26²)/(35² - 5²) = (74 - 26)(74 + 26) / (35 - 5)(35 + 5) = 48*100 / 30*40 = 3*4*4 / 3*4 = 4