Bjr
A =
[tex] \frac{ \frac{1}{5} - \frac{3}{4} }{ \frac{1}{5} + 1} [/tex]
A =
[tex] \frac{ - \frac{11}{20} }{ \frac{1}{5} + 1} [/tex]
A =
[tex] \frac{ - \frac{11}{20} }{ \frac{6}{5} } [/tex]
A =
[tex] - \frac{ \frac{11}{20} }{ \frac{6}{5} } [/tex]
A =
[tex] - \frac{11}{24} [/tex]
___________________________
B =
[tex] \frac{2 \times 10 {}^{ - 5} \times 1.2 \times 10 {}^{2} }{1 5\times10 {}^{ - 7} } [/tex]
B =
[tex] \frac{2.4 \times 10 {}^{ - 5} \times 10 {}^{2} }{15 \times 10 {}^{ - 7} } [/tex]
B =
[tex] \frac{2.4 \times 10 {}^{ - 5 + 2} }{15 \times 10 {}^{ - 7} } [/tex]
B =
[tex] \frac{ \frac{12}{5} \times 10 {}^{ - 5 + 2} }{15 \times 10 {}^{ - 7} } [/tex]
B =
[tex] \frac{ \frac{12}{5} \times 10 {}^{ - 3} }{15 \times 10 {}^{ - 7} } [/tex]
B =
[tex] \frac{ \frac{12}{5} \times 10 {}^{4} }{15} [/tex]
B =
[tex] \frac{ \frac{ 12 \times 10 {}^{4} }{5} }{15} [/tex]
B =
[tex] \frac{4 \times 10 {}^{4} }{25} [/tex]
B =
[tex] \frac{4 \times 10000}{25} [/tex]
B =
[tex]4 \times 400[/tex]
B =
[tex]1600[/tex]
B =
[tex]6.4 \times 10 {}^{3} [/tex]
Voilà !
