Question

calcular o valor de x , sabendo-se que :

a)3x+2/4=3-4x/5


b)7x-2/4x-4/3/5


c)5-4x/4x-4=7/2

Answer 1

$a) \\ 3x+ \frac{2}{4} =3- \frac{4x}{5} \\ \\ 3x+ \frac{2}{4} -3+ \frac{4x}{5} =0 \\ \\ \frac{3.5x+4x}{5} + \frac{2-3.4}{4} =0 \\ \\ \frac{19x}{5} - \frac{10}{4} =0 \\ \\ 4.19x-5.10=0 \\ \\ 76x=50 \\ \\ x= \frac{50}{76} = \frac{25}{38}$

$b) \\ 7x- \frac{2}{4}x- \frac{ \frac{4}{3} }{5} \\ \\ 7x- \frac{2}{4} x- \frac{4}{15} =0 \\ \\ [tex] \frac{28x-2x}{4} - \frac{4}{15} =0 \\ \\ \frac{26x}{4} - \frac{4}{15} =0 \\ \\ 15.26x-16=0 \\ \\ 15.26x=16 \\ \\ x= \frac{16}{15.26} = \frac{8}{15.13} = \frac{8}{195}$


$c) \\ \frac{5-4x}{4x} -4= \frac{7}{2} \\ \\ \frac{5-4x}{4x} -4- \frac{7}{2} =0 \\ \\ \frac{5-4x}{4x} - \frac{4.2-7}{2} =0 \\ \\ \frac{5-4x}{4x} - \frac{8-7}{2} =0 \\ \\ \frac{5-4x}{4x} - \frac{1}{2} =0 \\ \\ 2(5-4x)-4x=0 \\ \\ 10-8x-4x=0 \\ \\ 10-12x=0 \\ \\ 12x=10 \\ \\ x= \frac{10}{12} = \frac{5}{6}$