Question

Calcule o valor real de x em:
​

Answer 1

Resposta:

a.

\begin{gathered}\frac{x}{3} = \frac{3}{2} \\ \\ 2x=3\cdot3 \\ \\ 2x=9 \\ \\ x= \frac{9}{2}\end{gathered}

3

x

=

2

3

2x=3⋅3

2x=9

x=

2

9

b.

\begin{gathered}\frac{4x}{5} = \frac{x+1}{3} \\ \\ 4x\cdot3=5(x+1) \\ \\ 12x=5x+5 \\ \\ 12x-5x=5 \\ \\ 7x=5 \\ \\ x= \frac{5}{7}\end{gathered}

5

4x

=

3

x+1

4x⋅3=5(x+1)

12x=5x+5

12x−5x=5

7x=5

x=

7

5

c.

\begin{gathered}\frac{2-x}{x+5} = \frac{3}{4} \\ \\ 4(2-x)=3(x+5) \\ \\ 8-4x=3x+15 \\ \\ -4x-3x=15-8 \\ \\ -7x=7 \\ \\ 7x=-7 \\ \\ x=-1\end{gathered}

x+5

2−x

=

4

3

4(2−x)=3(x+5)

8−4x=3x+15

−4x−3x=15−8

−7x=7

7x=−7

x=−1

d.

\begin{gathered}\frac{x-1}{x-2} = \frac{3}{2} \\ \\ 2(x-1)=3(x-2) \\ \\ 2x-2=3x-6 \\ \\ 2x-3x=2-6 \\ \\ -x=-4 \\ \\ x=4\end{gathered}

x−2

x−1

=

2

3

2(x−1)=3(x−2)

2x−2=3x−6

2x−3x=2−6

−x=−4

x=4