Question

sa se calculeze :
ex 1 a si b

Answer 1

$a) { ({5}^{2}) }^{4} \times {5}^{8} \div {5}^{15}$

$= {5}^{2 \times 4} \times {5}^{8} \div {5}^{15}$

$= {5}^{8} \times {5}^{8} \div {5}^{15}$

$= {5}^{8 + 8 - 15}$

$= {5}^{16 - 15}$

$= {5}^{1}$

$= 5$

$b) {( {4}^{0} + {4}^{1} + {4}^{2} ) }^{5} \div {21}^{3} - {21}^{2}$

$= {(1 + 4 + 16)}^{5} \div {21}^{3} - {21}^{2}$

$= {21}^{5} \div {21}^{3} - {21}^{2}$

$= {21}^{5 - 3} - {21}^{2}$

$= {21}^{2} - {21}^{2}$

$= 0$