21p4q5r3 : ( 9p2qr3 : 3pqr )

21p 4q 5r^3 / (9p 2q r^3 : 3p q r) maka kerjakan yg didalam kurung trlebih dahulu, 9p 2q r^3 : 3p q r = 3p 2q r^2 lalu 21p 4q 5r^3 / 3p 2q r^2 = 7p 2q 5r

[tex] \frac{21p {}^{4} q {}^{5}r {}^{3} }{9p {}^{2} qr {}^{3} \div 3pqr} \\ = \frac{21p {}^{4} q {}^{5}r {}^{3} }{3p {}^{2}qr {}^{3} pqr} \\ = \frac{7p {}^{2} q {}^{4} }{pqr} \\ = \frac{7pq {}^{3} }{r} [/tex]