Question

Aflati x din proportiile:a) 4 intregi 1/2 supra 3 = 0,5 supra x ; b) x+1/x+3 = 4/5 Va rog sa ma ajute cineva.Multumesc.

Answer 1

$a) \frac{4 \frac{1}{2} }{3} = \frac{0.5}{x}$

$\frac{ \frac{4 \times 2 + 1}{2} }{3} = \frac{ \frac{5}{10} }{x}$

$\frac{ \frac{9}{2} }{3} = \frac{ \frac{1}{2} }{x}$

$\frac{9}{2} \times \frac{1}{3} = \frac{1}{2} \times \frac{1}{x}$

$\frac{3}{2} = \frac{1}{2x}$

$3 \times 2x = 2 \times 1$

$6x = 2$

$x = \frac{2}{6}$

$x = \frac{1}{3}$

$b) \frac{x + 1}{x + 3} = \frac{4}{5}$

$5(x + 1) = 4(x + 3)$

$5x + 5 = 4x + 12$

$5x - 4x = 12 - 5$

$x = 7$