Toán a,(-28/9).(-38/14) b, (-21/6).(-24/7) c, I-12/17I.(-34/9) 21/07/2021 By Abigail a,(-28/9).(-38/14) b, (-21/6).(-24/7) c, I-12/17I.(-34/9)
a) $(-\dfrac{28}{9}).(-\dfrac{38}{14})$ $=\dfrac{28.38}{9.14}$ $=\dfrac{2.38}{9}=\dfrac{76}{9}$ b) $(-\dfrac{21}{6}.(-\dfrac{24}{7})$ $=\dfrac{21.24}{6.7}$ $=\dfrac{3.4}{1.1}=12$ c) $|-\dfrac{12}{17}|.(-\dfrac{34}{9})$ $=\dfrac{12}{7}.(-\dfrac{34}{9})$ $=-\dfrac{12.34}{17.9}$ $=-\dfrac{4.2}{1.3}=-\dfrac{8}{3}$ Trả lời
Đáp án: Giải thích các bước giải: `a) (-28/9).(-38/14)=(28.38)/(9.14)=(4.7.2.19)/(3^2.2.7)=(4.19)/(3^2)=76/9` `b) (-21/6).(-24/7)=(21.24)/(6.7)=(3.7.2^3.3)/(2.3.7)=3.2^2=3.4=12` `c) |-12/17|.(-34/9)=(12/17).(-34/9)=(-12.34)/(17.9)=(-2^2.3.2.17)/(17.3^2)=(-2^3)/3=-8/3` Trả lời
a) $(-\dfrac{28}{9}).(-\dfrac{38}{14})$
$=\dfrac{28.38}{9.14}$
$=\dfrac{2.38}{9}=\dfrac{76}{9}$
b) $(-\dfrac{21}{6}.(-\dfrac{24}{7})$
$=\dfrac{21.24}{6.7}$
$=\dfrac{3.4}{1.1}=12$
c) $|-\dfrac{12}{17}|.(-\dfrac{34}{9})$
$=\dfrac{12}{7}.(-\dfrac{34}{9})$
$=-\dfrac{12.34}{17.9}$
$=-\dfrac{4.2}{1.3}=-\dfrac{8}{3}$
Đáp án:
Giải thích các bước giải:
`a) (-28/9).(-38/14)=(28.38)/(9.14)=(4.7.2.19)/(3^2.2.7)=(4.19)/(3^2)=76/9`
`b) (-21/6).(-24/7)=(21.24)/(6.7)=(3.7.2^3.3)/(2.3.7)=3.2^2=3.4=12`
`c) |-12/17|.(-34/9)=(12/17).(-34/9)=(-12.34)/(17.9)=(-2^2.3.2.17)/(17.3^2)=(-2^3)/3=-8/3`