a: =-30*7/15=-14
b: =1/6*1/3*2=1/9
a)
\(A=\dfrac{\left(-5\right).11}{11.\left(-5\right)}.\dfrac{\left(-30\right).7}{15}=\left(-2\right).7=-14\)
b)
\(B=\dfrac{\left(-1\right).\left(-15\right).19.2}{2.3.19.3.15}=\dfrac{15.19.2}{2.3.19.3.15}=\dfrac{1}{9}\)
\(9,\\ a,A=\left(\dfrac{-5}{11}\right).\dfrac{7}{15}.\left(\dfrac{11}{-5}\right).\left(-30\right)\\ =\left(\dfrac{-5}{11}.\dfrac{11}{-5}\right).\left[\dfrac{7}{15}.\left(-30\right)\right]\\ =\dfrac{-55}{-55}.\dfrac{-210}{15}\\ =1.\left(-14\right)\\ =-14\\ b,B=\left(-\dfrac{1}{6}\right).\left(-\dfrac{15}{19}\right).\left(\dfrac{38}{45}\right)\\ =\dfrac{-1.\left(-15\right).38}{6.19.45}\\ =\dfrac{15.38}{6.19.45}\\ =\dfrac{3.5.19.2}{2.3.19.3.3.5}\\ =\dfrac{1}{3.3}\\ =\dfrac{1}{9}\)
