Question

How do you solve `7x-1=9+2x`?

Answer 1

`color(green)(x=2`

Explanation:

`color(blue)(7x-1=9+2x`

Remember the golden rule of Algebra-what we do in one side must be done in the other side also.

Add `1` both sides:

`rarr7x-1+1=9+2x+1`

`rarr7x=10+2x`

Subtract `2x` both sides:

`rarr7x-2x=10+2x-2x`

`rarr5x=10`

Divide both sides by `5`:

`rarr(5x)/5=10/5`

`rarr(cancel5x)/cancel5=10/5`

`rArrcolor(green)(x=2`

Check:

Substitute the value of `x` into the equation:

`|->color(brown)(7(2)-1=9+2(2)`

`|->color(brown)(14-1=9+4`

`|->color(orange)(13=13` :)

So,it is true!