Question

Если a+b=5 ab=4 то чему равно a^3+b^3​

Answer 1

a + b = 5    a * b = 4

a³ + b³ = (a + b)(a² - ab + b²) = (a + b) * [(a + b)² - 3ab] = 5 * (5² - 3 * 4) =

= 5 * (25 - 12) = 5 * 13 = 65

a³ + b³ = 65