Question

Calcule o valor de x nas proporções
a)(x + 4)/6 = 8/9

b)(2x + 4)/5 = (x + 2)/3

Me ajudem por favor

Answer 1

Resposta:

a) 1,333...; b) -2.

Explicação passo a passo:

a) (x + 4)/6 = 8/9

(x + 4)9 = 6 . 8

9x + 36 = 48

9x = 48 - 36

9x = 12

x = 12 : 9

x = 1,333...

b) (2x + 4)/5 = (x + 2)/3 =

(2x + 4) . 3 = 5 . (x + 2)

6x + 12 = 5x + 10

6x - 5x = 10 - 12

x = - 2.

Answer 2

a)(x + 4)/6 = 8/9

$\mathsf{\dfrac{x+4}6=\dfrac89}\\\\\mathsf{x+4=\dfrac{8\cdot6}9}\\\\\mathsf{x+4=\dfrac{8\cdot2}3}\\\\\mathsf{x+4=\dfrac{16}3}\\\\\mathsf{x=\dfrac{16}3-4}\\\\\mathsf{x=\dfrac{16}3-\dfrac{12}3}\\\\\mathsf{x=\dfrac{16-12}3}\\\\\boxed{\boxed{\mathsf{x=\dfrac{4}3}}}$

b)(2x + 4)/5 = (x + 2)/3

$\mathsf{\dfrac{2x+4}5=\dfrac{x+2}3}\\\\\mathsf{15\cdot\dfrac{2x+4}5=15\cdot\dfrac{x+2}3}\\\\\mathsf{3(2x+4)=5(x+2)}\\\\\mathsf{6x+12=5x+10}\\\\\mathsf{6x+12-5x=10}\\\\\mathsf{x+12=10}\\\\\mathsf{x=10-12}\\\\\boxed{\boxed{\mathsf{x=-2}}}$