Please Help me i dont know this.

Step-by-step explanation:

First, expand out the brackets

2 x 1.6a = 3.2a

2 x 0.7 = 1.4

Therefore 3.2a - 1.4 = 8.2

Now solve to find a

3.2a - 1.4 = 8.2

3.2a = 9.6

a = 3

hope this helps :)

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: