21/-9x5+7(-9-11)x7.2=

$$\\21/-9\times 5+7(-9-11)\times 7.2\\\\ =\frac{21}{-9}\times 5+7\times(-20)\times 7.2\\\\ =\frac{21*5}{-9}+-140\times 7.2\\\\ =\frac{105}{-9}+-1008\\\\ =-11\frac{6}{9}-1008\\\\ =-11\frac{2}{3}-1008\\\\ =-1019\frac{2}{3}\\\\$$