Question

b)9/7-3/4=

c)8/5-7/8=

d)8/15-1/3-45/16

e)2/3-1/4-8/5=​

Answer 1

Resposta:

b)

$\frac{9}{7} - \frac{3}{4} = \\ \\ = \frac{4 \times 9 - 7 \times 3}{28} \\ \\ = \frac{36 - 21}{28} \\ \\ = \Large \boxed{ \green{ \bf \frac{15}{28} }}$

c)

$\frac{8}{5} - \frac{7}{8} = \\ \\ = \frac{8 \times 8 - 5 \times 7}{40} \\ \\ = \frac{64 - 35}{40} \\ \\ = \Large \boxed{ \green{ \bf \frac{29}{40} }}$

d)

$\frac{8}{15} - \frac{1}{3} - \frac{45}{16} = \\ \\ \frac{16 \times 8 - 80 \times 1 - 15 \times 45}{240} \\ \\ = \frac{128 - 80 - 675}{240} \\ \\ = \frac{128 - 755}{240} \\ \\ = - \frac{627 \div 3}{240 \div 3} \\ \\ = \Large \boxed{ \green{ \bf - \frac{209}{80} }}$

e)

$\frac{2}{3} - \frac{1}{4} - \frac{8}{5} = \\ \\ = \frac{20 \times 2 - 15 \times 1 - 12 \times 8}{60} \\ \\ = \frac{40 - 15 - 96}{60} \\ \\ = \frac{40 - 111}{60} \\ \\ = \Large \boxed{ \green{ \bf - \frac{ 71}{60} }} \\ \\ \Large \boxed{ \underline{ \bf \blue{ Bons \: Estudos!}13/05/2021}}$