Question

qual a resposta da equação ? a) x+30=40 b)30-20+2×=10 c) 3×-10+13=-2×+28. d)-2×=-4+3× e) -2×=-4+3× f) -5×+45-89=-90+41g)4×-8=10 h) 13×-23-45=-7×+12

Answer 1

a)
$x + 30 = 40 \\ x = 40 - 30 \\ x = 10$
b)
$30 - 20 + 2x = 10 \\ 10 + 2x = 10 \\ 2x = 0 \\ x = 0$
c)
$3x - 10 + 13 = - 2x + 28 \\ 3x + 3 = - 2x + 28 \\ 3x + 2x = 28 - 3 \\ 5x = 25 \\ x = \frac{25}{5} \\ x = 5$
d)
$- 2x = - 4 + 3x \\ - 2x - 3x = - 4 \\ - 5x = - 4 \\ x = \frac{4}{5} \\ x = 0.8$
e)
$- 2x = - 4 + 3x \\ - 2x - 3x = - 4 \\ - 5x = - 4 \\ x = \frac{4}{5} \\ x = 0.8$
f)
$- 5x + 45 - 89 = - 90 + 41 \\ - 5x - 44 = - 49 \\ - 5x = - 49 + 44 \\ - 5x = - 5 \\ x = 1$
g)
$4x - 8 = 10 \\ 4x = 10 + 8 \\ 4x = 18 \\ x = \frac{9}{2} \\ x = 4.5$
h)
$13x - 23 - 45 = - 7x + 12 \\ 13x - 68 = - 7x + 12 \\ 13x + 7x = 12 + 68 \\ 20x = 80 \\ x = 4$