Question

Efectuati:a)[17×(25-8×3)×1la2021-15]×2la3-2la2×3;b)[(9la2-2la4×5)÷1+5la9÷(5la2)la4]×2la2

Answer 1

$a)[17 \times (25 - 8 \times 3) \times {1}^{2021} - 15 ] \times {2}^{3} - {2}^{2} \times 3$

$= [17 \times (25 - 24) \times 1 - 15] \times 8 - 4 \times 3$

$= (17 \times 1 - 15) \times 8 - 12$

$= (17 - 15) \times 8 - 12$

$= 2 \times 8 - 12$

$= 16 - 12$

$= 4$

$b)[( {9}^{2} - {2}^{4} \times 5) \div 1 + {5}^{9} \div {( {5}^{2} )}^{4} ] \times {2}^{2}$

$= (81 - 16 \times 5 + {5}^{9} \div {5}^{2 \times 4} ) \times 4$

$=(81 - 80 + {5}^{9} \div {5}^{8} ) \times 4$

$= (1 + {5}^{9 - 8} ) \times 4$

$= (1 + {5}^{1} ) \times 4$

$= (1 + 5) \times 4$

$= 6 \times 4$

$= 24$