Mohonn bantuannya kak

Mohonn bantuannya kak

Jawab:
(19.) = 27
(20.) = 4x¹⁰ ÷ y⁸
(21.) = ¹/₂₇
(22.) = ⁴/₂₇

Penjelasan dengan langkah-langkah:

$displaystyle (19.) ~largeboxed{81^{frac{5}{6}}times81^{frac{2}{3}}div81^{frac{3}{4}}=}\hugeboxed{81^{frac{5(2)}{6(2)}+frac{2(4)}{3(4)}-frac{3(3)}{4(3)}} =} \hugeboxed{81^{frac{10}{12}+frac{8}{12}-frac{9}{12}} = 81^{frac{9}{12}}}\largeboxed{= 81^{frac{9div3}{12div3}}= 81^{frac{3}{4}}=(3^4)^{frac{3}{4}} }\= 3^3 =bf 27$

$displaystyle(20.)sf~~frac{64x^6y^{-3}}{4^2x^{-4}y^{5}}=frac{4^3x^6y^{-3}}{4^2x^{-4}y^{5}}$
= 4³⁻²x⁶⁻⁽⁻⁴⁾y⁻³⁻⁵
= 4¹x⁶⁺⁴y⁻⁽³⁺⁵⁾ = 4x¹⁰y⁻⁸
$displaystylebf frac{4x^{10}}{y^8}$

(21.) 3⁴ × 3⁶ ÷ 3¹³ =
3⁴⁺⁶⁻¹³ = 3¹⁰⁻¹³ = 3⁻³
$displaystylefrac{1}{3^3}=bffrac{1}{27}$

(22.) 3⁻² + 3⁻³ =
$displaystylesf frac{1}{3^2}+frac{1}{3^3}=frac{3^1}{3^{2}times3^1}+frac{1}{3^3}\\=frac{3}{3^{2+1}}+frac{1}{3^3}=frac{3}{3^{3}}+frac{1}{3^3}\\= frac{3+1}{3^3}bf=frac{4}{27}$

(xcvi)