Question

-9(3x+2)=
-4(2+3x)=
3(3x-7+2x)=
5(-10x+8+6x)=
6(5x+5)=
4(x-10)=20​

Answer 1

Usando a distributiva:

a)

$- 9(3x + 2) = - 27x- 18 = \\ - 27x = 18 \: \times ( - 1) \\ 27x = - 18 \\ x = \frac{ - 18}{27} \: \div ( \frac{9}{9} ) \\ x = \frac{ - 2}{3}$

b)

$- 4(2 + 3x) = - 8 - 12x = \\ - 12x = 8 \: \times ( - 1) \\ 12x = - 8 \\ x = \frac{ - 8}{12} \: \div ( \frac{4}{4} ) \\ x = \frac{ - 2}{3}$

c)

$3(3x - 7 + 2x) = 9x - 21 + 6x = \\ 9x + 6x = 21 \\ 15x = 21 \\ x = \frac{21}{15} \: \div ( \frac{3}{3} ) \\ x = \frac{7}{5}$

d)

$5( - 10x + 8 + 6x) = - 50x + 40 + 30x = \\ - 50x + 30x = - 40 \\ - 20x = - 40 \: \times ( - 1) \\ 20x = 40 \\ x = \frac{40}{20} \: \div ( \frac{20}{20} ) \\ x = \frac{2}{1}$

e)

$6(5x + 5) = 30x + 30 = \\ 30x = - 30 \\ x = \frac{ - 30}{30} \\ x = - 1$

f)

$4(x - 10) = 20 \\ 4x - 40 = 20 \\ 4x = 20 + 40 \\ 4x = 60 \\ x = \frac{60}{4} \\ x = 15$