Question

Resolvam por favor.
Agradeço.

Answer 1

b) 
$\frac{x+1}{3} = \frac{x-1}{4}$
(x + 1) × 4 = 3 × (x - 1)
4x + 4 = 3x - 3
4x - 3x = - 3 - 4
x = - 7

c)
$\frac{x+1}{x+2} = \frac{10}{12}$
(x + 1) × 12 = (x + 2) × 10
12x + 12 = 10x + 20
12x - 10x = 20 - 12
2x = 8
x = $\frac{8}{2}$
x = 4

d)
$\frac{x+3}{x-1} = \frac{x}{x+2}$
(x + 3) × (x + 2) = (x - 1) × x
x² + 2x + 3x + 6 = x² - x
x² + 5x + 6 = x² - x
x² - x² + 5x + x + 6 = 0
6x + 6 = 0
6x = - 6
x = $\frac{-6}{6}$
x = - 1