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+41



g)4×-8=10



h) 13×-23-45=-7×+12

Answer 1

a. 

$x+30=40 \\ x = 40-30 \\ x = 10$

b.

$30-20+2x=10 \\ 10+2x = 10 \\ 2x=10-10 \\ 2x = 0 \\ x = 0$

c.

$3x-10+13=-2x+28 \\ 3x+2x=28+10-13 \\ 5x = 25 \\ \\ x = \dfrac{25}{5} = 5$

d. 

$-2x=-4+3x \\ 3x+2x=4 \\ 5x = 4 \\ \\ x = \dfrac{4}{5} = 0,8$

f.

$-5x+45-89=-90+41 \\ 5x=45-89+90-41 \\ 5x = 5 \\ x = 1$

g.

$4x-8=10 \\ 4x = 10+8 \\ 4x = 18 \\ \\ x = \dfrac{18}{4} = 4,5$

h.

$13x-23-45=-7x+12 \\ 13x+7x=12+23+45 \\ 20x=80 \\ \\ x = \dfrac{80}{20} = 4$