Bài 2:
Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:
\(\dfrac{a}{1}=\dfrac{b}{-3}=\dfrac{a-2b}{1-2\cdot\left(-3\right)}=\dfrac{14}{7}=2\)
Do đó: a=2; b=-6
a) A=11/9.[(-3/2)-15/2]+0
A= 11/9.[(-3/2)-15/2]
A=11/9.(-9)
A=-11
Đó bạn^^
\(a,A=\dfrac{11}{9}\left(-\dfrac{3}{2}-\dfrac{15}{2}\right)=\dfrac{11}{9}\cdot\left(-9\right)=-11\\ b,B=\left(1,6:0,4\right)^2-\dfrac{57}{4}+\dfrac{7}{5}-\dfrac{7}{4}=16-16+\dfrac{7}{5}=\dfrac{7}{5}\\ c,C=\left(-10\right)\left(-0,15\right)+\left(2,7+4,3\right)+8,5=1,5+7+8,5=7+10=17\\ d,D=\dfrac{2^{10}\cdot3^8-2\cdot2^9\cdot3^9}{2^{10}\cdot3^8+2^8\cdot3^8\cdot2^2\cdot5}=\dfrac{2^{10}\cdot3^8\left(1-3\right)}{2^{10}\cdot3^8\left(1+5\right)}=\dfrac{-2}{6}=-\dfrac{1}{3}\)
