Question

17 Determinati numärul natural x, care verificã egalittile: 3^x+2 - 5 • 3^x =36

VA ROG DAU COROANA

Answer 1

$3 {}^{x + 2} - 5 \times 3 {}^{x } = 36 \\ 3 {}^{x} (3 {}^{2} - 5) = 36 \\ 3 {}^{x} (9 - 5) = 36 \\ 3 {}^{x} \times 4 = 36 \\ 3 {}^{x} = 9 \\ 3 {}^{x} = 3 {}^{2} \\\underline {x = 2}$