Question

Alguem me ajuda nisso?

Answer 1

Vamos lá!

a)

$\frac{3x}{4} = 30 \\ 3x = 30 \times 4 \\ 3x = 120 \\ x = \frac{120}{3} \\ \blue{ \boxed{ \boxed{x = 40}}}$

b)

$\frac{x}{3} = 7 \\ x = 7 \times 3 \\ \blue{ \boxed{ \boxed{x = 21}}}$

c)

$\frac{2x}{5} = 4 \\ 2x = 4 \times 5 \\ 2x = 20 \\ x = \frac{20}{2} \\ \blue{ \boxed{ \boxed{x = 10}}}$

d)

$\frac{x}{4} = - 3 \\ x = - 3 \times 4 \\ \blue{ \boxed{ \boxed{x = - 12}}}$

e)

$\frac{2x}{3} = - 10 \\ 2x = - 10 \times 3 \\ 2x = - 30 \\ x = \frac{ - 30}{2} \\ \blue{ \boxed{ \boxed{x = - 15}}}$

f)

$\frac{2x}{5} = - 18 \\ 2x = - 18 \times 5 \\ 2x = - 90 \\ x = \frac{ - 90}{2} \\ \blue{ \boxed{ \boxed{x = - 45}}}$

Answer 2

Explicação passo-a-passo:

A)

$\dfrac{3x}{4} = 30$

$3x = 4 \times 30$

$3x = 120$

$x = \dfrac{120}{3}$

$x = 40$

B)

$\dfrac{x}{3} = 7$

$x = 3 \times 7$

$x = 21$

C)

$\dfrac{2x}{5} = 4$

$2x = 5 \times 4$

$2x = 20$

$x = \dfrac{20}{2}$

$x = 10$

D)

$\dfrac{x}{4} = - 3$

$x = 4 \times - 3$

$x = - 12$

E)

$\dfrac{2x}{3} = - 10$

$2x = 3 \times - 10$

$2x = - 30$

$x = - \dfrac{30}{2}$

$x = - 15$

F)

$\dfrac{2x}{5} = - 18$

$2x = 5\times - 18$

$2x = - 90$

$x = - \dfrac{90}{2}$

$x = - 45$