Step-by-step explanation:
18.
[tex] = { ({x}^{2}) }^{ - 3} .2 {x}^{3} [/tex]
[tex] = {x}^{2 \times ( - 3)} .2 {x}^{3} [/tex]
[tex] = {x}^{ - 6} .2 {x}^{3} [/tex]
[tex] = 2 {x}^{ - 6 + 3} [/tex]
[tex] = 2 {x}^{3} [/tex]
[tex] = \frac{2}{ {x}^{3} } [/tex]
[tex] \: [/tex]
19.
[tex] = {(2m)}^{2} . {(3 {m}^{3} )}^{2} [/tex]
[tex] = {2}^{2} {m}^{2} . {3}^{2} {m}^{3 \times 2} [/tex]
[tex] = 4 {m}^{2} .9 {m}^{6} [/tex]
[tex] = (4 \times 9) {m}^{2 + 6} [/tex]
[tex] = 36 {m}^{8} [/tex]
