Question

How to do 2/5 = (x-3)/(7x+15)

Answer 1

x = -5

Step by step:

multiply both side by 7x + 15.

2/5 (7x+15)= x − 3

Simplify 2)5 (7x+15) to 2(7x+15)/5.

2(7x+15)/5= x - 3

multiply both sides by 5.

2(7x+15)= 5x - 15

Expand.

14x+30= 5x - 15

subtract 5x from both sides.

14x+30−5x= − 15

Simplify 14x + 30 - 5x14x + 30−5x to 9x + 309x + 30.

9x+30= - 15

Subtract 30 from both sides.

simplify

x = -5

Answer 2

`x = - 5`

Explanation:

To work out this question you have to first cross multiply.

`(2)/(5) = \frac{(x - 3)} {(7x + 15)} \\ \\ 2(7x + 15) = 5(x - 3)`

When you cross multiply you will get the equation above. Therefore

`(2 * 7x) + (2 * 15) = (5 * x) \\ - (5 * 3) \\ \\ 14x + 30 = 5x - 15 \\ \\ 14x - 5x = - 30 - 15 \\ \\ 9x = - 45`

Therefore

`(9)/(9) x = ( - 45)/(9) \\ \\ x = - 5`